Hierarchical Timed Coloured Petri Nets Research Articles

Simulation Based Analysis of Hierarchical Timed Colored Petri Nets Model of the Restaurant Food Serving Process

The major goal of establishing a restaurant is improved earnings making which can be jeopardized by customers' withdrawals due to lengthy ready lines. The above scenario was studied in this paper using simulation-based analysis of a Hierarchical Timed Coloured Petri Nets (HTCPN) model, which abstracted the serving operation of a renowned restaurant in the Ibadan metropolis. The restaurant was characterized by two or more servers that serially served each Customer from the multiple available servers at the four serving points. One hundred simulation runs were carried out on the HTCPN model using CPN Tools to determine the four (4) parameters,Customers' Average Flow Time (CAFT),Customers' Average Waiting Time (CAWT),Servers' Average Utilization Rate (SAUR) andCustomers' Average Queue Length (CAQL) required in serving 567, 1100, 1103, 770 and 829 customers from Monday to Friday, respectively. The model was validated by carrying out a statistical analysis t-Test between the simulated and the actual customers' flow time andservers' utilization rate at a 5% significant level. The validation results showed no significant differences between the simulated and the actual customers' average flow time andservers' utilization rate at a 5% significance level. Hence, the model can represent the restaurant under consideration.

A hierarchical formal method for performance evaluation of WSNs protocol

The design and the evaluation of communication protocols in WSNs is a crucial issue. Generally, researchers use simulation methods to evaluate them. However, formal modelling and analysis techniques are an efficient alternative to simulation methods. Indeed, these techniques allow performance evaluation and model verification. In this paper, a formal approach is proposed to modelling and to evaluating the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) MAC protocol with a star topology. Moreover, the proposed approach deals with some properties that are not stated in most existing works. The approach uses Hierarchical Timed Coloured Petri Nets (HTCPNs) formalism to model the protocol and exploits the CPN-Tools to analyse the generated models. HTCPNs provide timed aspect which facilitates the consideration of time constraints inherent to the CSMA/CA protocol.

Development of a Model for an Inbound Call Centre Using Hierarchical Timed Coloured Petri Nets

Inbound call centres are centralized offices which are operated by modern organizations to administer incoming product supports or information inquiries from consumers. In this paper, a model for an inbound call centre, which is characterized by agent utilization and call abandon rates, was developed using Hierarchical Timed Coloured Petri Nets (HTCPN). The inbound call section of SN Nigeria Ltd., Lagos, Nigeria, was used as a case study in developing the HTCPN model. Data were collected and analyzed statistically using ARENA simulation software to determine the model parameters. These parameters were used as inputs in developing the HTCPN model which consists of Call Arrival, Hang up Processes, Sales Processes, Customercare and Enterprise Process modules. The model was simulated using Colour Petri Nets tools and validated by carrying out a statistical analysis (t-Test) between the simulated and the real number of abandon calls and agents utilization rates at 5% significance level. The simulation results of the developed HTCPN model revealed that increase in number of agents utilized resulted into decrease in abandon calls from 71, 7 and 108 to 35, 4 and 102 in customer care, enterprise and sales departments, respectively. Correspondingly, increase in number of utilized agents led to reduction in agents’ utilization rates from 96, 50 and 96% to 84, 40 and 92% for customer care, enterprise and sales departments, respectively. The result of the validation showed that there were no significant differences between the simulated and the real number of abandoned calls and agents utilization rates.

Correction to: Using Hierarchical Timed Coloured Petri Nets in the formal study of TRBAC security policies

In the original publication of this article, the third author’s name was incorrectly published.

Using Hierarchical Timed Coloured Petri Nets in the formal study of TRBAC security policies

Role-Based Access Control (RBAC) is one of the most used models in designing and implementation of security policies, in large networking systems. Basic RBAC model does not consider temporal aspects which are so important in such policies. Temporal RBAC (TRBAC) is proposed to deal with these temporal aspects. Despite the elegance of these models, designing a security policy remains a challenge. Designers must ensure the consistency and the correctness of the policy. The use of formal methods provides techniques for proving that the designed policy is consistent. In this paper, we present a formal modelling/analysis approach of TRBAC policies. This approach uses Hierarchical Timed Coloured Petri Nets (HTCPN) formalism to model the TRBAC policy, and the CPN-tool to analyse the generated models. The timed aspect, in HTCPN, facilitates the consideration of temporal constraints introduced in TRBAC. The hierarchical aspect of HTCPN makes the model “manageable”, in spite of the complexity of TRBAC policy specification. The analysis phase allows the verification of many important properties about the TRBAC security policy.

Modelling and Simulation of Deposit Slip Mode of Bank Cash Deposit Transactions Using Hierarchical Timed Coloured Petri-Nets

Significant investments are being made yearly to improve service quality and delivery in banking systems to minimise customers' dissatisfactions with long waiting time due to overcrowding. However, most existing empirical studies to address this problem employed the method where the system was modelled and then developed a program that will simulate, analyse and validate the developed model. This paper conceptualised modelling bank cash deposit transactions characterised by Deposit Slip (DS) using Hierarchical Timed Coloured Petri Nets (HCPN). The HTPC model developed was simulated using Coloured Petri Nets tools. The model was validated by comparing the simulated results with the real average flow time of the customers and utilisation rate of servers using statistical t-test at p< 0.05.
 This model is useful for bank decision makers in capacity building to enhance service quality and delivery.

Design an intelligent real-time operation planning system in distributed manufacturing network

PurposeWith the new generation Industry 4.0 coming, as well as globalization and outsourcing, products are fabricated by different parties in the distributed manufacturing network and enterprises face the challenge of consistent planning of semi-finished product in each manufacturing process in different geographical locations. The purpose of this paper is to propose a real-time operation planning system in the distributed manufacturing network to intelligently control/plan the manufacturing networks.Design/methodology/approachThe feature of the proposed system is to model and simulate large distributed manufacturing networks to streamline the mechanical and production engineering processes with radio frequency identification (RFID) technology, which can keep track of process variants. To deal with concurrency and synchronization, the hierarchical timed colored Petri net (HTCPN) formalism for modeling is selected in this study. This method can help to model graphically and test the discrete events of concurrent operations. Fuzzy inference system can help for knowledge representation, so as to provide knowledge-based decision assistance in distributed manufacturing environment.FindingsIn this proposed system, there are two main sub-systems: one is the real-time modeling system, and the other one is intelligent operation planning system. These two systems are not parallel in the whole systems while the intelligent operation planning system should be embedded in any stage of the real-time modeling system as needed. That means real time modeling system provides the holistic structure of the studied distributed manufacturing system and realize real-time data transfer and information exchange. At the same time the embedded intelligent operation planning system fulfill operation plan function.Originality/valueThis new intelligent real-time operation system realizes real-time modeling with RFID-based HTCPN and smart fuzzy engine to fulfill intelligent operation planning which is highly desirable in the environment of Industry 4.0. The new intelligent manufacturing architecture will highly reduce the traditional planning workload and improve the planning results without manual error interference. The new system has been applied in a practical case to demonstrate its feasibility.

Identification of detailed behaviour of Flexible Manufacturing Cell using Hierarchical Timed Coloured Petri Nets

The goal of this paper is focused on identifying the behavioural structure of a flexible manufacturing cell (FMC) using a model based on Coloured Timed Petri Nets and applying hierarchical techniques. In the paper we explain the modelling procedure of the manufacturing cell with single resource for different types of parts according to proposed decisions on places and transition in order to analyse the overall processing time in the cell. The designed model is based on a manufacturing cell from Faculty of Managerial and Technological Engineering, University of Oradea. In this present work, we present the behaviour of resource places, transitions and evaluate overall performance of the flexible manufacturing cell using CPNTools software.

IoT-Enabled Real-Time Production Performance Analysis and Exception Diagnosis Model

The recent developments of technologies in Internet of Things (IoT) provide the opportunities for smart manufacturing with real-time traceability, visibility, and interoperability in production planning, execution, and control. To fulfill this target, this work presents a real-time production performance analysis and exception diagnosis model (PAEDM). By this model, hierarchical-timed-colored Petri net (HTCPN) with smart tokens that change just like smart objects in practice is used to analyze the sensor data such that the critical performance information can be perceived. Decision Tree is used to diagnose exceptions from the critical production performance, so that persuasive qualitative and quantitative exception information can be extracted accurately. The presented method is demonstrated by a case study and simulation results show that PAEDM can be used to effectively analyze production performance and exceptions in real-time for dynamic and stochastic manufacturing processes.

Modelling and analysis of air traffic control systems using hierarchical timed coloured Petri nets

Hierarchical timed coloured Petri net (HTCPN) models have been utilized as a visual formalism for the modelling of complex reactive systems. They brighten the features on describing properties of causality, concurrency and synchronization. This paper focuses on the use of HTCPNs to model and analyse a dynamic procedure of an air traffic control (ATC) system. The advantage of the proposed approach is the clear presentation of the aircraft behaviour in terms of conditions and events. To our knowledge, this is the first work that employs HTCPNs to obtain models of ATC systems.