Object-oriented Petri Nets Research Articles

Modeling and Key Technologies of Intelligent Assembly System for Mechanical Products

Manufacturing is country's pillar industries and the core driving force of national economic development. Among them, the machinery manufacturing industry provides technical equipment for the development of the whole country, which plays a decisive function of the development of the national economy and the progress of science and technology. As the increased competition in the global market, the machinery manufacturing industry is facing unprecedented severe challenges. Assembly has a great impact on product quality and the characteristics of complex operating processes, as it is the last part of the mechanical product manufacturing process and therefore often determines the level of mechanically manufactured products. The purpose of this paper is to improve the intelligence level of assembly systems through the development and application of Internet of Things technology. Take the mechanical product assembly system as the research object, the research methods are as follows: First, on the basis of analyzing the connotation and characteristics of manufacturing associations, proposed the manufacturing environment of the Internet of Things. Then, constructed the overall operation framework, network physical environment and topology structure are of the system, and refined the key technologies of system modeling. Object-oriented Petri nets and VisObjNet simulation techniques are used for abstract modeling and simulation systems. Finally, developed the prototype of the intelligent assembly system of mechanical products under the Internet of Things background, and further verified the feasibility and effectiveness of the method proposed in this paper. The research results show that the prediction accuracy of the online monitoring system can reach 98.8% by collecting acceleration and noise in real time. The efficient and green processing parameter optimization system greatly optimizes the original processing efficiency. The method proposed in this paper effectively improves the transparency of the mechanical product assembly process. It provides a reference model and implementation path for building a smart assembly system for mechanical products under the IoT environment.

A security event description of intelligent applications in edge-cloud environment

In traditional network environment, the attack topology of the network is usually obtained based on a graph traversal algorithm. It uses connection relationships to describe the process of the attack, thus completing the description of network security event. However, in the edge-cloud environment, the control logic and data forwarding of network devices are separated from each other. The control layer is responsible for the centralized management of network edge nodes. After acquiring the entire network topology, it can automatically generate a visualized network structure. This architecture extends traditional cloud computing architecture to the edge of the network, helping to handle some latency-sensitive service requirements, especially for most IoT applications. Therefore, security analysts can grasp the connection status of the devices on the entire network in the control domain. This network topology generation method based on the control layer information is directly and efficiently, which can greatly simplify the description of security events in the edge-cloud environment. At the same time, the separate structure also hides specific details of the underlying network device. Petri-net, as a formal description tool, can be used to describe such structure. Among existing security event description methods, the CORAS modeling tool has the advantages of graphical description, reusability and refinement description. And it also provides analysis guides to guide the operation steps. Based on the edge-cloud environment, this paper combines the advantages of CORAS modeling and analysis with Object-oriented Petri-net theory, and proposes a COP (CORAS-based Object-oriented Petri-net)-based Intelligent Applications security event description method. Experiments verify that this method is suitable for describing the complexity and dynamics of security events in edge cloud environment.

MapReduce rationality verification based on object Petri net

As a powerful distributed data processing mechanism, MapReduce supports abundant parallel applications that process massive data on computer clusters. To process the massive data efficiently and correctly, a rational design for the MapReduce procedure is desired. An irrational MapReduce procedure can cause great waste of computing resources and even paralyze the execution system. With the wide application of MapReduce, the unavoidable drawback of irrational MapReduce procedures becomes increasingly serious. To solve this problem, a method for verifying the rationality of a MapReduce procedure before executing it on a computer cluster is proposed. This method constructs the rationality criteria for MapReduce, and then studies an automatic approach for modelling MapReduce with an executable model object Petri net (OPN). Finally, the approaches for automatically identifying the rationality criteria by analyzing the consequence of model execution is developed. The results from extensive case studies demonstrate that the proposed method is feasible and effective.

Petri Net Model of a Smart Factory in the Frame of Industry 4.0

Industry 4.0 advocates an intensive use of information and communication technologies in manufacturing facilities for achieving sustainability and success in a market with exigent and informed consumers willing personalized products and services. Three main concepts of the Industry 4.0 paradigm are addressed: cyber-physical systems, the Internet of Things, and virtualization. A Petri net model of a smart factory regarding the Industry 4.0 paradigm is proposed as virtualization for decision making support. Enhanced computing and communication capabilities of machines and products allow implementing the approach of mass customization. Any product is associated to a sequence of services, being able to request them to the appropriate machines. The formalism of the object Petri nets has been chosen, where a token net is associated to the product and a system net to the facility. The resulting model can be considered for analysis, performance evaluation, and decision making support.

Formal modeling and control of cyber-physical manufacturing systems

Cyber-physical manufacturing systems are a new paradigm of manufacturing systems that integrate cyber systems and physical systems to aid smart manufacturing. Cyber-physical manufacturing systems can improve agility and responsiveness and guarantee the quality of products to meet the market requirements. Meanwhile, cyber-physical manufacturing systems also become susceptible to cyber-attacks. In order to improve the trustworthiness of cyber-physical manufacturing systems in the dynamic modeling phase, a cyber-physical manufacturing system formal model based on object-oriented Petri nets is presented from the perspective of multi-agent systems. Some mathematical methods and supporting tools of Petri nets can be utilized to analyze, verify, and validate cyber-physical manufacturing system formal model. To defense the malicious software spreading in cyber-physical manufacturing systems at run-time, a spreading dynamics model is proposed, and its dynamic behaviors are analyzed. A hybrid bifurcation control me...

Object-oriented Petri nets and π-calculus-based modeling and analysis of reconfigurable manufacturing systems

Reconfigurable manufacturing systems can change the structure of the systems to cope with manufacturing market requirements. Reconfigurability brings about new challenges for reconfigurable manufacturing systems’ development. In order to describe, analyze, and verify the reconfiguration of reconfigurable manufacturing systems, a reconfigurable manufacturing system formal model is proposed from the perspective of multi-agent systems, in which two complementary formalisms, namely, object-oriented Petri nets and π-calculus, are employed as formalisms. The object-oriented Petri nets are utilized to model the initial structure as well as system behaviors of reconfigurable manufacturing systems, while π-calculus is adopted to describe the reconfiguration of reconfigurable manufacturing systems. Some supporting tools of Petri nets and π-calculus can be used to analyze, verify, and validate the reconfigurable manufacturing system formal model. The reconfigurability mechanism and consistency of reconfigurable manufacturing systems can also be analyzed by π-calculus.

Designing reconfigurable manufacturing systems using reconfigurable object Petri nets

In reconfigurable manufacturing systems (RMSs), the structure of the system can be changed during its execution. This reconfiguration can be triggered by several motivations: a new requirement in the production process, avoiding some problems caused by machines breakdowns, etc. RMSs are characterised by their flexibility which guarantees productivity and efficiency. However, their design is more complicated and needs new techniques and paradigms. The use of high level Petri nets (PNs) offers the ability to design these systems and to analyse their properties. In this article, the authors apply reconfigurable object nets (RONs) for the modelling, simulation and analysis of RMSs. Indeed, a formal method is proposed, where the reconfiguration process is specified explicitly as a graph transformation, the simulation is realised using the RON-tool, and the analysis exploits the TINA-tool (timed nets analyser tool).

XML jako formát vyjádření objektových Petriho sítí

A number of object-oriented (OO) variants have so far been devised for Petri Nets (PN). However, none of these variants has ever been described using an open, independent format – such as XML. This article suggests several possibilities and advantages of such a description. The outlined XML language definition for the description of object-oriented Petri Nets (OOPN) is based on XMI (description of UML object-oriented models), SOX (simple description of general OO systems) and PNML (an XML-based language used for the description of structured and modular PN). For OOPN, the XML form of description represents a standard format for storing as well as for transfer between various OOPN-processing (analysis, simulation, ...) tools.

Předpoklady Petriho sítí k modelování logistických systémů

Simulation and optimization is one of the most popular approaches to improve the use of simulation models as a tool to obtain the best system configuration. Petri nets have proved to be useful for examining the performance of different system configurations and/or alternative operating procedures for various systems. Based on their precise semantics and easy-to-understand graphical representation, Petri nets are appropriate to model logistic systems together with their quantitative and qualitative properties. In this paper, potential benefits of usage of object-oriented Petri nets for optimization of logistical systems are discussed.

XML formát pro záznam objektové Petriho sítě

Petri nets provide executive facilities for simulation of causality, non-determinism and parallelism in discreet systems. Since they are a mathematical model in substance, they offer theory, which can be successfully used to verification of models. Executability of Petri nets predestinates them for simulation and fast prototyping. Object Petri nets represent rather complicated class, based on hierarchical and high-level Petri nets. However their complexity is balanced by their ability to identify significant characteristics of system model and to visualize it in a graphic representation.Tools currently applied to modeling, simulation and verification of various Petri net variants use language PNML (Petri Net Markup Language) as an interchange format. However PNML is not capable of expression of object Petri net. This paper introduces prototype of XML-based language for modeling of parallel object-oriented systems described by object Petri net. This language, based on PNML, was named OPNML (Object Petri Net Markup Language).

Optimisation of water usage in a brewery clean-in-place system using reference nets

Abstract The brewery industry is becoming increasingly aware of its water and energy usage due to stricter regulations, and environmental and economic incentives. An area where large improvements in water usage presents itself is the clean-in-place system. A significant portion of the total process water required in an industrial sized brewery is used during clean-in-place processes. Testing and optimisation of these industrial processes can be quickly and economically achieved using computer modelling and simulation tools. One such tool is the reference net, a subclass of object-oriented Petri nets. In order to predict the water usage and the potential for energy production from wastewater attributed to the clean-in-place plant in a brewery, the reference net formalism is used. Validation of the complete reference net system is undertaken using two sets of simulations, one set of simulations running an approximation of a standard brewery clean-in-place system and a second set implementing a fuzzy logic adaptive control for water reuse. The reference net is found to be a valid and efficient tool for quick prototyping of new and existing industrial sized brewery clean-in-place systems.

Petri net based decision system modeling in real-time scheduling and control of flexible automotive manufacturing systems

This paper presents the design and the implementation of a Petri net (PN) model for the control of a flexible manufacturing system (FMS). A flexible automotive manufacturing system used in this environment enables quick cell configuration, and the efficient operation of cells. In this paper, we attempt to propose a flexible automotive manufacturing approach for modeling and analysis of shop floor scheduling problem of FMSs using high-level PNs. Since PNs have emerged as the principal performance modeling tools for FMS, this paper provides an object-oriented Petri nets (OOPNs) approach to performance modeling and to implement efficient production control. In this study, we modeled the system as a timed marked graph (TMG), a well-known subclass of PNs, and we showed that the problem of performance evaluation can be reduced to a simple linear programming (LP) problem with m−n+1 variables and n constraints, where m and n represent the number of places and transitions in the marked graph, respectively. The presented PN based method is illustrated by modeling a real-time scheduling and control for flexible automotive manufacturing system (FAMS) in Valeo Turkey.

Modeling and Simulation of Reducer’s Production Process Based on Object-Oriented Petri Net

In order to deal well with the complexity in modeling a reducer’s production process, this paper proposes an Object-oriented Petri Net (OOPN) approach by combining object-oriented concept with Petri net theory. At first, the definitions of OOPN were given. Then, the procedure of modeling the production process with OOPN was described in detail, and the model analysis was conducted. Finally, the Flexsim software was used to simulate this model in order to find out the bottlenecks of the reducer’s process planning and some suggestions were proposed, which will lay a foundation on the optimization of its process planning.

Modeling in Mixed-Model Assembly Lines Based on Object-Oriented Petri Net

In order to model clearly in mixed-model assembly lines, this paper proposes an Object-oriented Petri Net (OOPN) approach by combining object-oriented concept with Petri net theory. Firstly, the mathematical definition of OOPN was given. Secondly, taking automobile transmission mixed-model assembly lines as an example, the modeling through three different levels of assembly cells, assembly resources and the whole system was finished, and the message delivery mechanism and system behavior were then described in detail. Finally, the case study shows that OOPN can deal well with the complexity of modeling, and it lays the foundation of further analysis and property verification in the mixed-model assembly lines.

A Petri Net-based Approach for Event Detection in Pedestrian Crossing Sequence

In this paper we present an approach to automatically detect anomalous traffic events like pedestrians crossing the junction, based on traffic video of low-level features such as size of the blob, spatial location, and velocity. The construction of Petri-Nets was used for both semantic description and event detection within traffic videos. The major novelties of this paper are extensions to both the modeling and the recognition capacities of Object Petri-Nets (PN). The detection of object level features are done with the help of state of art techniques like Gaussian Mixture of Models (GMM), and a series of Petri-Nets composed of various objects is proposed to describe the video content. The expected outcome of the proposed framework is that we can easily build semantic detectors based on PNs to search within traffic videos and identify interesting events. Experimental results based on recorded traffic video data sets and synthetic data sets are used to illustrate the potential of this framework.

Extended knowledge attributed Petri Nets

Choosing the best way for describing physical reality has always been standing in focus of research. Several methodologies have been developed based on classical mathematics, or statistics and also new disciplines — such as soft-computing techniques — appeared. Petri Nets as one of the most naturalistic modeling methodologies are well suited to describe complex process in general. However in some fields of modeling the describing power of basic Petri Nets proved not to be robust enough, therefore several extensions were made to the original concept. Colored tokens (Colored Petri Nets), stochastic delayed streaming of mobile entities (Stochastic Petri Nets), object oriented architecture (Object Oriented Petri Nets), numerical (Numerical Petri Nets) and linguistic attributes (Fuzzy Petri Nets) broaden the range of capabilities. In some fields of problem solving, usage of static and mobile knowledge bases is needed: e.g., flexible manufacturing systems, or intelligent traffic simulation. These problems to be investigated involved new conceptual developments of Petri Nets and led to the introduction of Knowledge Attributed Petri Nets. At the same time distributed control in simulation appeared, intelligent agents supported the connection of mobile knowledge bases and static inference engines in an effective way. The mentioned extensions brought general support in model synthesis, but some unsolved questions remained related to the implementation of intelligent mobile entities. This paper highlights a new level of AI controlled simulation introducing the Extended Knowledge Attributed Petri Nets that offer the capability of easy implementation of mobile inference engines and knowledge base, providing general mobile AI in Petri Nets.

Adaptive e‐learning system based on agents and object petri nets (AELS‐A/OPN)

AbstractAgent technology plays an important role in today's software development at the industrial level and brings advantages to the development of educational applications. The main focus of the multi‐agent systems community has been on the development of concepts, architectures, interaction techniques, and general approaches to the analysis and specification of multi‐agent systems. We introduce herein a novel concept involving the development of an e‐Learning system architecture that explores several recent technologies, including multi‐agent technology and adaptive e‐Learning. The main concern of our research is twofold: to build a multi‐agent architecture that provides the ability to adapt to the learner's preferences in the e‐Learning environment and to analyze and control the communication and interactions among the different agents of the proposed system. Toward this aim, we present a distributed intelligent blackboard agent that ensures the communication among the participating agents. Furthermore, we describe a formal model that can be used to specify the message exchanges and their synchronization using Object Petri Nets. An exploratory implementation has been developed and conducted in practice. © 2013 Wiley Periodicals, Inc. Comput Appl Eng Educ 23:170–190, 2015; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.21587

Research on the Integration of Object-Oriented Petri Nets and QUEST

As object-oriented simulation software adopts event-driven simulation method, it can not show the logical and temporal relations among the objects clearly, and the formal description of the system is not sufficient, that leads to low reliability and the establishment of a perfect simulation model may need several modifications and debugging. According to the problems that exist in the object-oriented simulation software, a modeling and simulation technology is presented based on Petri Net and QUEST in this paper, which combines Petri Net’s rigorous description with QUEST’s visual feature. Base on the practical application requirements in visual C++ environment，to realize the integration of the object oriented Petri model and the QUEST model.

A New Control Structure Model Based on Object-oriented Petri Nets

Petri nets in object-oriented modeling, based on the objects introduced a special internal changes - the control changes, the introduction of objects in the controller, a control structure based on object-oriented Petri nets (CS-OOPN) model, and described the CS-OOPN modeling steps of the described of CS-OOPN modeling. The model overcomes the traditional object-oriented Petri nets modeling of flexible processes and systems lack the flexibility of the shortcomings can be more intuitive, flexible to describe the work flow. Finally, using this model for a group management system and for modeling equipment procurement, and approval departments CS-OOPN model as an example, find its associated matrix, tree coverage and P-invariant, the correlation analysis to prove that building the model has good performance and to meet the system requirements change and restructuring.

Research on Manufacture Processes of Resin Dry Transformers Based on Object-Oriented Petri Net

The models of resources and manufacturing processes, which aim at the production system of the resin dry transformers, are constructed by Object-oriented Petri Net (OPN) in this paper. SCB9 1000/10 400(Cu) transformer is taken as case study, the flow chart of manufacturing transformers are described at first, and then researched by static analysis, dynamic analysis and integrated application in details. The conflicts of the OPN models, which may happen in all manufacturing system of resin dry transfers, have been resolved. The whole manufacturing system are improved and optimized in the manufacture processes at last.