Reggie Davidrajuh

University of Stavanger · Department of Electrical engineering and Computer science

This paper presents a simulation model to study the effect of the battery charging rate of Automated Guided Vehicles (AGVs) on the overall output of a toy car production environment. This paper uses Modular Petri Nets for modeling and the General Petri Net Simulator (GPenSIM) for model implementation on MATLAB and simulation. The main focus of this...

General-purpose Petri net Simulator (GPenSIM) is a toolbox (set of functions) that runs on MATLAB. Some universities use GPenSIM as the tool for modeling, simulation, and performance analysis of discrete systems. Academics in these universities chose GPenSIM as it is easy to learn, use, and extend. Also, the fact that GPenSIM runs on MATLAB allows...

Petri nets are a promising modeling framework for epidemiology, including the spread of disease across populations or within an individual. In particular, the Susceptible-Infectious-Recovered (SIR) compartment model is foundational for population epidemiological modeling and has been implemented in several prior Petri net studies. However, the SIR...

Petri nets are a promising modeling framework for epidemiology, including the spread of disease across populations or within an individual. In particular, the Susceptible-Infectious-Recovered (SIR) compartment model is foundational for population epidemiological modeling and has been implemented in several prior Petri net studies. However, the SIR...

Efficient multiprocessor scheduling is pivotal in optimizing the performance of parallel computing systems. This paper leverages the power of Petri nets and the tool GPenSIM to model and simulate a variety of multiprocessor scheduling algorithms (the basic algorithms such as first come first serve, shortest job first, and round robin, and more soph...

This paper presents a comprehensive simulation study of Automated Guided Vehicles (AGVs) in a fabricated production environment for toy car assembly. This paper uses Petri Nets for modeling and the General Petri Net Simulator (GPenSIM) for model implementation on MATLAB and simulation. The primary focus of this research is to analyze the operationa...

The video game Factorio is a popular real-time strategy game that hosts a variety of gameplay scenarios analogous to real-world problems such as factory building, pipeline optimization, and conveyor belt logistics. It also considers environmental costs such as pollution and energy consumption. This game focuses on automation and resource management...

Petri Nets are well known as a tool to model discrete systems. Petri Nets possess arc weights that represent the number of tokens consumed by a transition from its input place (input arc weight) or deposited into its output place (output arc weight). The arc weights are fundamental during the simulation run (‘dynamic analysis’) of the Petri Net. Pe...

This paper uses colored Petri nets (PN) to develop a model of vehicle movement in a city. The modeler defines the number and location of crossroads, the connections between them, and how many vehicles are at the given points of the network. The vehicles are recognized by their license plate numbers, and it is possible to determine where they start...

It can happen that an activity represented by a transition may be very lightweight in the sense its firing cost could be negligible. However, this activity may use an expensive resource to perform. In this case, the total costs of the activity (transition costs + the resource usage costs) will be dominated by the resources.

In engineering systems, there are always resources. For example, in a manufacturing system, humans are needed to operate machines and robots for some activities; printers are common resources in a computer’s Local Area Network (LAN). In a P/T Petri net, resources are usually represented by places, with some initial token equaling the available inst...

GPenSIM facilitates compact Petri net models by removing the resources (usually represented as places) from the Petri nets and treating them as variables during run-time. This approach is useful for modeling systems that employ many resources (e.g., manufacturing systems).

The General-purpose Petri net Simulator (GPenSIM) is a new tool for the modeling, simulation, and performance analysis of discrete systems. GPenSIM runs on the MATLAB platform. GPenSIM is also a real-time controller with which external software and hardware can be controlled. Some universities use GPenSIM because of its simplicity, flexibility, and...

This chapter models two classical problems of synchronization with Colored Petri nets using the coloring facilities in GPenSIM. These two classical problems are often discussed in computer science literature. The problems are (1) Producers-Consumers and (2) Cigarette Smokers.

This chapter starts with some advantages and disadvantages of using GPenSIM. Then, this chapter presents some well-known applications of GPenSIM for modeling, simulation, and analysis of discrete systems. Also, some further works are suggested.

No simulator for discrete-event systems is complete unless it provides built-in support for cost calculations. This is because, in engineering and industry, we study the performance of discrete-event systems to save time and resources, ultimately saving money (costs). GPenSIM provides a simple and effective mechanism for cost calculation in simulat...

It is clear from the previous chapters that GPenSIM offers a very limited form of token color, namely only text strings. This chapter shows one way to come around this limitation, by using indexed coloring. Indexed coloring is a hybrid approach in which the color of each token points (is an index) to a structure that can hold any data. Hence, inste...

This chapter discusses token selection based on time. Previous chapters on Colored Petri nets looked into the functionality for selecting tokens with colors, where color refers to the text strings tagged on the tokens. We can also let a transition select tokens from input places based on time; time here refers to which token is the oldest (the ones...

This chapter discusses the selection of tokens from multiple input places, as the previous two chapters dealt with selecting tokens from a single input place. The following Sects. 4.1 and 4.2 explain how we can let a transition consume tokens (based on colors) from different input places.

Being a modern Petri net simulator, GPenSIM is designed and developed with efficient algorithms and data structures. When developing new software, data structures are of fundamental importance.

In P/T Petri Nets, tokens inside a place are indistinguishable: all the tokens inside a place are homogenous (the same). It does not matter which token arrived at the place first or last. It does not matter either whether a token is deposited in the place by one transition or another.

Drilling operations are the major cost factor for the industry. Appropriately designed operations are essential for successful drilling. Optimized drilling operations also allow enhanced drilling performance and reduce drilling costs. This is achieved by increasing the bit life (minimizing premature bit wear), faster drilling, which allows a reduct...

Drilling operation is the major cost factor for the industry. Appropriately designed operations are essential for successful drilling. Optimized drilling operations also allow enhanced drilling performance and reduce the drilling cost. This is achieved by increasing the bit life (minimizing premature bit wear), drilling faster that allows reducing...

Dear Colleagues, I on behalf of the Special Session Team and CSCWD 2022 committee would like to invite you to submit both original research and work in progress manuscripts to this Special Issue on "Business Intelligence Perspectives: Building from A Computer Supported Collaborative Point of View". The IEEE Computer Supported Cooperative Work in De...

Swab and surge pressure fluctuations are decisive during drilling for oil. The axial movement of the pipe in the wellbore causes pressure fluctuations in wellbore fluid; these pressure fluctuations can be either positive or negative, corresponding to the direction of the movement of the pipe. For example, if the drill string is lowering down in the...

Modern Production systems are large, and the mathematical models of these become huge. Hence, the models become useless as they are challenging to analyze and perform model verification. Moreover, some of these production systems are inherently discrete (e.g., discrete production systems), while others can be discretized (e.g., Robotics). Petri net...

This chapter is about putting the Petri modules together in a modular Petri net. This chapter consists of three groups of sections. In the first section, nine blocks are introduced as the basic building blocks of a discrete system. The second section introduces six matrices, such as Adjacency, Laplacian, Reachability, Rader’s, Connection, and Compo...

This chapter presents complete details about modular Petri nets, providing the formal definitions to all the elements (such as Petri Module, Inter-Modular Connector, and the modular Petri net). An application example on modular Petri net is also given in Sect. 7.4. Some technical issues like hosting the different modules on different computers are...

With the conclusion from the literature study done in the previous chapter (Sect. 5.5 “Research Gap: Conclusions of Literature Study”) and the research goals identified in Sect. 3.5 “Research Goals of this book”, this chapter takes the first attempt to design a modular Petri net. This chapter introduces the main elements of a modular Petri net, suc...

This chapter introduces the General-purpose Petri net Simulator (GPenSIM). Only the basics of GPenSIM are given in this chapter; for a detailed study of GPenSIM, [9] is recommended. The development of GPenSIM is influenced by [27]. GPenSIM defines a Petri net language for modeling and simulation of discrete event systems on the MATLAB platform. GPe...

Sometimes, it may not be possible to modularize a legacy Petri net model due to its crisscrossing internal connections between the elements inside it. For example, a system may have a topology of connections that is close to a complete graph. A complete graph is a graph in which every node is directly connected with all other nodes. A complete grap...

Modularization of a monolithic model starts with identifying segments (groups of elements) of the model that can become the modules; the modules are supposed to decompose the model into a set of connected independent modules. Literature provides some techniques for identifying segments of a model that can become modules (e.g., [4, 5, 6]).

This chapter presents the extension to GPenSIM to support developing modular Petri nets. This chapter discusses the programming constructs provided by GPenSIM for the development of modular Petri net models. As discussed in Chap. 4 “GPenSIM for Monolithic Petri nets”, GPenSIM did not support modularization before. GPenSIM was extended to support mo...

This chapter presents GPenSIM for modeling monolithic (non-modular) Petri nets. It is important to understand how GPenSIM supported the development of monolithic (non-modular) Petri nets as this knowledge will help us understand the extensions to support modules later on. This chapter focuses on the processor files (such as specific processor files...

This chapter introduces the basic concepts of Petri nets. This chapter starts with the formal definitions of some of the key concepts (such as P/T Petri nets, enabled transitions, and state space). The state equation and the structural properties (P-invariant and t-invariant) are introduced. Also, a short introduction to strongly connected event gr...

P/T Petri nets do not provide any support for modularization. Modular model building with Petri nets has a short history, starting with works in the late 1990s. This chapter presents an extensive literature review on this topic. The conclusions drawn from the literature study is summarized at the end of this chapter. These conclusions are the basis...

This chapter presents a generic three-layered architecture for Petri modules that can participate in collaboration while performing some useful functions on their own. This chapter starts with a crude structure for Petri modules and discusses the necessity of using colored Petri net. Finally, the generic architecture is presented.

This chapter focuses on the property of collaborativeness. Collaborativeness is a property of a module, indicating whether the module is willing or be able to participate in collaboration with the other modules. This chapter applies the theories and techniques developed in the previous chapters of this book to solve the problem of model checking fo...

This chapter presents five new algorithms for analyzing the network connectivity in the modular Petri net models. These algorithms are simple yet powerful enough to solve fundamental networking problems in modular Petri net models of large discrete event systems (e.g., discrete manufacturing systems). The algorithms are designed with Industry 4.0 i...

This chapter presents some Petri net models of typical manufacturing systems (such as flexible manufacturing system, circular AGVs, and cyclic processes). The reason behind this chapter is to clearly show the major difficulties in using Petri nets for modeling real-life discrete event systems generally and manufacturing systems specifically. All th...

This book offers a new Modular Petri Net as a solution to the vast Petri net models. It presents some approaches centering around modules (known as “Petri modules”). The goal of this book is to introduce a methodology in which Petri nets are moved to a new level. In this new level, large Petri net models are made of Petri modules, which are indepen...

Cloud Computing provides on-demand computing services like software, networking, storage, analytics, and intelligence over the Internet (“the cloud”). But it is facing challenges because of the explosion of the Internet of Things (IoT) devices and the volume, variety, veracity and velocity of the data generated by these devices. There is a need for...

Petri nets, even though very useful for modeling of discrete event systems, suffer from some weaknesses such as huge size, huge state space, and slow in simulation. Due to the huge state space, model checking a Petri net is difficult. Also, due to the slowness in simulation, discrete-timed Petri nets cannot be used for real-time applications. Thus,...

In reconfigurable manufacturing systems (RMSs), the architecture of a system can be modified during its operation. This reconfiguration can be caused by many motivations: processing rework and failures, adding new products, adding new machines, etc. In RMSs, sharing of resources may lead to deadlocks, and some operations can therefore remain incomp...

The invention of reconfigurable manufacturing systems (RMSs) has created a challenging problem: how to quickly and effectively modify an RMS to address dynamic changes in a manufacturing system, such as processing failures and rework, machine breakdowns, addition of new machines, addition of new products, removal of old machines, and changes in pro...

Various deadlock control policies for automated manufacturing systems with reliable and shared resources have been developed, based on Petri nets. In practical applications, a resource may be unreliable. Thus, the deadlock control policies proposed in previous studies are not applicable to such applications. This paper proposes a two-step robust de...

Large-scale manufacturing systems involve hardware and software that are highly interconnected and complex. Unexpected failures in these systems can cause material damages and can risk human lives too. The definite way of avoiding unexpected failures is to make a model of the system and to perform model verification and validation on it. Petri nets...

Deadlock control approaches based on Petri nets are usually implemented by adding control places and related arcs to the Petri net model of a system. The main disadvantage of the existing policies is that many control places and associated arcs are added to the initially constructed Petri net model, which significantly increases the complexity of t...

Petri net is a highly useful tool for modeling of discrete-event systems. However, Petri net models of real-life systems are enormous, and their state-spaces are usually of infinite size. Thus, performing analysis on the model becomes difficult. Hence, slicing of Petri Net is suggested to reduce the size of the Petri nets. However, the existing sli...

The objective behind this paper is to present a MATLAB Toolbox for elevator simulations; this toolbox is known as ‘ElevatorSIM’, and it is still under development. ElevatorSIM is based on the GPenSIM, which is software for modeling, simulation, performance analysis, and control of discrete-event systems. In this paper: firstly, the software GPenSIM...

Graph theory provides some methods for finding clusters in networks. Clusters reflect the invisible grouping of the elements in a network. This paper presents a new method for finding clusters in networks. In this method, the user can adjust a parameter to change the number of clusters. This method is newly added to the simulator General-purpose Pe...

The goal of this paper is to compare the two simulation environments of FlexSim and GPenSIM, for manufacturing simulations. A discrete-event system in material handling is taken as a case study, and this system is modeled and simulated with FlexSim and GPenSIM. The motivation of this paper is to share the experiences from this simulation study. Fir...

This paper presents an efficient Alpha-algorithm for process mining. Firstly, a short literature review is given on the available algorithms for process mining. Secondly, a new polynomial-time algorithm is proposed, which is efficient as it takes only O(LT2 + T3) time, where L and T are the number of traces (rows) of the event log and the total num...

This paper presents a new approach for modeling discrete manufacturing systems using Petri nets. Starting with the literature review of the classical approaches, this paper describes the new approach known as Activity-Oriented Petri Nets (AOPN). The AOPN approach provides expressive Petri net models that are powerful enough for modeling complex and...

After concisely reviewing the related work, the job shop transient scheduling problem and the model of production system of repetitive production are discussed. The activity-oriented Petri net (AOPN) simulation approach for optimization of transient dispatching rules is given. The software tool GPenSim and computational experiments with the results...

This chapter presents the functions that are available in GPenSIM for finding the structural invariants (e.g., siphons, traps, place invariants (P-invariants), and transition invariants (T-invariants). Structural invariants (aka net invariants) are the structural properties of a Petri net that depend only on the static (topological) structure; stru...

This chapter introduces the processor files of the GPenSIM. With the processors, many real-life discrete-event systems could be modeled as Petri nets. The processors also give GPenSIM the flexibility it is well known for and the potential for making hybrid Petri net models by combining Petri nets with the other MATLAB Toolboxes (e.g., Fuzzy Logic,...

The parameters that can be adjusted are known as the OPTIONS in GPenSIM.

This chapter discusses performance evaluation of discrete-event systems with GPenSIM. The topics such as P/T Petri nets, marked graphs, and strongly connected components are presented. Also, some of the GPenSIM functions that are available for performance evaluation are presented. These functions can be used to find the flow rate, the existence of...

This chapter presents some of the extensions and restrictions to the P/T Petri nets. GPenSIM supports some of these extensions (e.g., colored Petri net, Petri net with inhibitor arc, enabling functions, transitions with priorities) and restrictions (marked graphs, state machines). Due to its flexibility, it is easy to implement the other extensions...

This chapter presents two of the functions (tools) that are available in the GPenSIM for the analysis of Petri nets: coverability tree and firing sequences. In coverability tree analysis, we determine the states that are reachable from a given initial state. The firing sequence is executing a sequence of transitions, to study the state space genera...

This chapter introduces the basic aspects of modeling discrete-event systems with GPenSIM. In GPenSIM, a clear separation of the static and the dynamic details is practiced.

This chapter discusses interfacing a Petri net model in GPenSIM with the external environment. First, the internal data structures of a Petri net in GPenSIM are described. Also discussed is how the Petri net model developed with GPenSIM can be interconnected with software (e.g., MATLAB Toolboxes) and with hardware (e.g., LEGO Mindstorm robot).

Petri nets are a useful tool for the modeling and performance evaluation of discrete event systems. Literature reveals that the Petri Net models of real-world discrete event systems are most frequently event graphs (a subclass of Petri nets). Literature also reveals that there are some simple methods for the performance evaluation of event graphs....

Communicating agents are an important part of intelligent machines. However, modeling communicating agent with Petri nets is not an easy task as the modeling usually yields large yet less expressive models. In this paper, a modular Petri net approach is introduced for modeling communicating agents. The new approach is implemented in the tool Genera...