Computational Complexity of Liveness Problem of Normal Petri Net

2009 ◽  
Vol E92-A (11) ◽  
pp. 2717-2722 ◽  
Author(s):  
Atsushi OHTA ◽  
Kohkichi TSUJI
Keyword(s):  
Computational Complexity ◽  
Petri Net

scholarly journals Global Supervisory Structure for Decentralized Systems of Flexible Manufacturing Systems Using Petri Nets

Processes ◽  
2019 ◽  
Vol 7 (9) ◽  
pp. 595 ◽  
Author(s):  
Muhammad Bashir ◽  
Liang Hong
Keyword(s):  
Computational Complexity ◽  
Petri Nets ◽  
Petri Net ◽  
Flexible Manufacturing ◽  
Flexible Manufacturing Systems ◽  
Manufacturing Systems ◽  
Structural Complexity ◽  
Decentralized Systems ◽  
The Cost ◽  
Global Controller

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.

Optimal enforcement of liveness for decentralized systems of flexible manufacturing systems using Petri nets

2020 ◽  
Vol 42 (12) ◽  
pp. 2206-2220
Author(s):  
Muhammad Bashir
Keyword(s):  
Computational Complexity ◽  
Petri Nets ◽  
Petri Net ◽  
Supervisory Control ◽  
Flexible Manufacturing ◽  
Flexible Manufacturing Systems ◽  
Manufacturing Systems ◽  
Common Elements ◽  
Decentralized Controllers ◽  
The Given

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.

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
Keyword(s):  
Computational Complexity ◽  
Petri Nets ◽  
Petri Net ◽  
Production Systems ◽  
Fuzzy Petri Net ◽  
Minimum Number ◽  
Reasoning Technique

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.

Bipolar Abstract Argumentation with Dual Attacks and Supports

2020 ◽  
Author(s):  
Nico Potyka
Keyword(s):  
Computational Complexity ◽  
Decision Problems ◽  
Abstract Argumentation ◽  
Stable Semantics ◽  
Support Relations ◽  
Support Relationships ◽  
Computational Properties ◽  
Inherent Tendency

Bipolar abstract argumentation frameworks allow modeling decision problems by defining pro and contra arguments and their relationships. In some popular bipolar frameworks, there is an inherent tendency to favor either attack or support relationships. However, for some applications, it seems sensible to treat attack and support equally. Roughly speaking, turning an attack edge into a support edge, should just invert its meaning. We look at a recently introduced bipolar argumentation semantics and two novel alternatives and discuss their semantical and computational properties. Interestingly, the two novel semantics correspond to stable semantics if no support relations are present and maintain the computational complexity of stable semantics in general bipolar frameworks.

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