Petri Net Objects Research Articles

BEHAVIORAL VERIFICATION OF INTERNET OF THINGS SYSTEMS BY PETRI NETS

The rapid development, implementation in all spheres of human activity and the growing responsibility of the functions of the Internet of things systems tighten and complicate the requirements for the reliability of their design decisions at the development stages and operability during the implementation of implementations. Well-known methods of verification of projects and implementations are based on the means of systemic, structural, functional, design and technological analysis and synthesis of Internet of things systems. However, their capabilities do not underestimate the feasibility of developing formalized models and verification methods. This study presents the elements of technology and the steps of the behavioral verification methodology of functional level projects for Internet of things systems represented using Petri nets. General verification is represented by three stages - the analysis of the correctness of the general structural and functional properties, the actual verification of inter-level and inter-component interactions, behavioral online and offline testing in the class of functional type errors. In the proposed analysis, the basic entities and relationships of the Internet of things systems are determined and verified architectural level, defining the structure, components, functions, interfaces, asynchronous-event interactions and represent elements of Petri nets - their positions, transitions, arcs, functions, markup. Online and offline testing for dynamic verification of the behavior of the Internet of things systems is carried out on the basis of, respectively, the background or special formation of many process threads in the Petri net, activated during its modeling and covering the Petri net objects. This paper presents general estimates of resource and time costs for the design of Internet of things systems without verification and with verification, showing their reduction in the event of design errors, redesign and application of verification. Verification is illustrated by the example of Petri nets simulating an automatic lighting system.

Modeling of Object-Oriented Programs with Petri Net Structured Objects

The article presents a method for constructing a model of an object-oriented program in terms of multilabeled Petri nets. Only encapsulation - one of the three concepts of object-oriented paradigm - is considered. To model a different aspects of encapsulation a Petri net structured object is proposed. It consists of a Petri net defining its behavior and a set of organized access points specifying its structural properties. Formal composition operations to construct a program model from the models of its methods, classes, objects, functions, and modules are introduced and a source code translation algorithm to Petri net representation is proposed. A special section of the article considers in detail a process of model construction of a real object-oriented program (OOP). Source code of the program, figures with Petri net objects modeling different elements of the program and the resulting model of the program are presented.

Asynchronous-Channels Within Petri Net-Based GALS Distributed Embedded Systems Modeling

Model-based development approaches can provide a major contribution in the development of globally asynchronous locally synchronous distributed embedded systems (GALS-DES) if supported by suited modeling formalisms and design automation tools. The use of Petri nets (either low-level or high-level classes) extended with asynchronous-channels (ACs), time domains, priorities, inputs, and outputs is proposed in this paper to model GALS-DES (composed by deterministic components), ensuring that the created GALS model is locally deterministic, distributable, network-independent, and platform-independent. The proposed ACs, with high level of abstraction, specify the components interaction through Petri net objects with specific attributes that unambiguously identify this interaction within the GALS model. Two algorithms are proposed to translate and decompose the GALS model into Petri net models without ACs, which can be used as inputs in model-checking tools and automatic code generators supporting GALS-DES verification and implementation. The specification of a small goods lift distributed controller illustrates the use of the proposed ACs.

Object Oriented Software Architecture Design based on UML/Petri Net approach for deadlock prevention of Real Time Systems

The objective of this article is to present an approach based on UML dynamic diagrams and on Petri Net Objects for the deadlock prevention of Real Time Systems. The main idea consists of translating the sequence diagrams which express the initial specifications of the system in a unique Petri Net model which represents the global behaviour of the entire system and which belongs to the special class of Petri Nets called Simple Sequential Process with Resources. After the detection of possible unmarked siphons in the structure of the global model, a deadlock prevention strategy based on the addition of local control places is applied in order to remove structural deadlocks. The augmented Petri Net model is then translated into a set of collaboration and state-transition diagrams which represent the final deadlock free UML specification. Finally, a software architecture free of deadlocks based on an object which contains the global behaviour of the system and which centralises all the interactions between the software objects is presented. The approach is illustrated through an example of Real Time System used at the global coordination level of a Batch System.

Didactic Integration, Control, and Implementation of Flexible Manufacturing Cells

This paper describes the development of a didactic cellular flexible manufacturing system that uses Petri nets to model and execute its scheduling and coordination activities. The system is composed of machining and assembly flexible manufacturing cells, each of them being controlled by a control software. The cell controller receives instructions from a Petri net object specified by the cell operator via a text file. The cell controller is intelligent in the sense that the operator can easily reconfigure the control logic, by writing a new text file describing de control net.

Interactive hypermedia applications: A model and its implementation

AbstractBy referring to the object‐oriented efforts of the Multimedia and Hypermedia information coding Expert Group (MHEG), and the augmented Petri net model, we present a formal definition of the multimedia hypermedia Petri net (MHPN) model. Through this proposed model, issues of authoring, rendering and synchronization of multimedia information (i.e. structure authoring, spatial temporal relationships, user interaction, etc.) can all be laid to rest. We have implemented a testbed system, the Petri net object information system (POIS), which offers considerable potential for the development of distributed hypermedia applications. The testbed has been implemented on an IBM‐PC486 under Windows 3.1. We are now in the process of porting the testbed model to Windows NT.

Object model for hypermedia applications

To illustrate how hypermedia applications are developed, details of a multimedia document architecture are first introduced, including the physical and logical structures of hypermedia, and its temporal requirements. The MH object classes of the Multimedia and Hypermedia information coding Expert Group (MHEG), an ISO standard, are then introduced in view of the heterogeneity of applications and platforms available. With reference to the latter, and an augmented Petri net model, we present a formal definition of the Multimedia Hypermedia Petri-Net model (MHPN). Through this proposed model, issues of authoring, rendering and the interaction of multimedia information (i.e. spatial-temporal relationships, stoppage, reverse display of a dynamic representation, and others, such as coauthoring and networking) can all be implemented. Moreover, based on the MHPN model, we describe an experimental object-oriented multimedia information system, called the Petri net Object Information System (POIS). We believe this offers considerable potential for the development of distributed hypermedia applications.

A Petri net-based simulation tool for the design and analysis of flexible manufacturing systems

Abstract Simulation is an invaluable tool in designing and analyzing manufacturing systems. A Petri net-based simulation tool is presented to aid simulation projects in manufacturing, including flexible manufacturing systems (FMSs). Three models are developed—an object model, Petri net model, and control model. While hardware components of FMSs are modeled by Petri net objects, control functions are separately modeled and integrated with a Petri net model to resolve conflicts occurring in Petri net execution. Facilities of the developed tool are presented, and a modeling procedure with the tool is illustrated via a case study.