Colored Petri Nets Research Articles

Latte

Emerging software-defined and programmable networking technologies enable more adaptive communication infrastructures. However, leveraging these flexibilities and operating networks more adaptively is challenging, as the underlying infrastructure remains a complex distributed system that is a subject to delays, and as consistency properties need to be preserved transiently, even during network reconfiguration. Motivated by these challenges, we propose Latte, an automated approach to minimize the latency of network update schedules by avoiding unnecessary waiting times and exploiting concurrency, while at the same time provably ensuring a wide range of fundamental consistency properties like waypoint enforcement. To enable automated reasoning about the performance and consistency of software-defined networks during an update, we introduce the model of timed-arc colored Petri nets: an extension of Petri nets which allows us to account for time aspects in asynchronous networks, including characteristic timing behaviors, modeled as timed and colored tokens. This novel formalism may be of independent interest. Latte relies on an efficient translation of specific network update problems into timed-arc colored Petri nets. We show that the constructed nets can be analyzed efficiently via their unfolding into existing timed-arc Petri nets. We integrate Latte into the state-of-the-art model checking tool TAPAAL, and find that in many cases, we are able to reduce the latency of network updates by 90% or more.

Generative capacity of kolam patterns using Tile pasting rules

Kolam is the art introduced and developed by south Indian People to entertain themself during the festival seasons. Even now it is regularly followed by the villagers especially by women every day morning In front of their houses using the rice flower. This paper gives an over view of drawing such patterns using colored petri nets and tile pasting system.

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.

More Efficient On-the-Fly Verification Methods of Colored Petri Nets

Colored Petri Nets (CP-nets or CPNs) are powerful modeling language for concurrent systems. As for CPNs' model checking, the mainstream method is unfolding that transforms a CPN into an equivalent P/T net. However the equivalent P/T net tends to be too enormous to be handled. As for checking CPN models without unfolding, we present three practical on-the-fly verification methods which are all focused on how to make state space generation more efficient. The first one is a basic one, based on a standard state space generation algorithm, but its efficiency is low. The second one is an overall improvement of the first. The third one sacrifices some applicability for higher efficiency. We implemented the three algorithms and validated great efficiency of latter two algorithms through experimental results.

Formal Approach Based on Petri Nets for Modeling and Verification of Video Games

Video games are complex systems that combine technical and artistic processes. The specification of this type of system is not a trivial task, making it necessary to use diagrams and charts to visually specify sets of requirements. Therefore, the underlying proposal of this work is to present an approach based on the formalism of Petri nets for aiding in the design process of video games. The activities of the game are represented by a specific type of Petri net called WorkFlow net. The definition of a topological map can be represented by state graphs. Using Colored Petri nets, it is possible to define formal communication mechanisms between the model of activity and the model of the map. The simulation of the timed models allows then to produce an estimated time that corresponds to the effective duration a player will need to complete a level of a game. Furthermore, a kind of Soundness property related to gameplay in a game Quest can be verified through state space analysis. For a better understanding of the approach, the video game Silent Hill II is used.

Colored Petri Nets Model for Network Based FTI Systems

Network based data acquisition system is a system which allows a data exchange using Ethernet technology. One of the main usage areas of this type of system is Flight Test Instrumentation (FTI) applications. There exists some complexity in analysis and synthesis of the entire system. Colored Petri Net (CPN) is a compact modelling method for Discrete Event Systems (DES). A model of a FTI network fabric is considered in this work in order to reduce related complexities. A CPN model for network based FTI system is presented and all states for this model are obtained in this work.

Improving the Correctness of Medical Diagnostics Based on Machine Learning With Coloured Petri Nets

Advanced software and storage technologies have enabled medical facilities to record and store vast amounts of data about cancer patients. There is a strong demand for an accurate and interpretable method to perform cancer prognostic for effective treatment. Machine learning algorithms, undoubtedly, demonstrate a remarkable ability to recognize models and extract patterns from data to improve medical prognosis decision-making. But machine learning outcomes are prone to bias and inaccurate labelling. Therefore, to negate the impact of such errors in the prognostic decision-making process, the mechanism to correct such errors is in high demand. This article addresses this problem by proposing the use of Coloured Petri nets formalism to ensure the correctness of the machine learning based prognostic process. Use of formalism makes it possible to ensure that prognostic decisions are correct and understandable. Empirical results show that we have increased the accuracy of prognostic decisions by up to 90%. This research supports improved prognostic decision-making for the effective treatment and identification of cancer patients.

Implications of loosened Role-based Access Control session control implementation for the enforcement of Dynamic Mutually Exclusive Roles properties on Health Information Systems

Role-based Access Control (RBAC) session control is used in the authorization vetting of controlled objects within the system to check if a user intended action is permitted by the associated roles that he/she possesses. The session control is also used to enforce Separation of Duty (SoD) via the Dynamic Mutually Exclusive Roles (DMER), limiting the roles that can be associated with a particular user during a session due to its conflicted permission nature. The RBAC requirements that dictate session controls functions preventing conflicted roles to be assigned to users can be poorly implemented because of possible interpretation of the RBAC standard. This loosened interpretation is here discussed by assessing RBAC function textual description and objectives and by formally stating the different interpretations using Z notation and Colored Petri Nets (CPN) to effectively demonstrate the resulting functionality and its reflexes on system use. Three different aspects of security properties are discussed comparing the interpretations and impacts on the RBAC functionality: a) the implications of user's authorization characterization on system's session, b) the actual DMER conflict detection capability, and c) possible collusion scenarios considering RBAC administrator capabilities. Two different interpretations of the RBAC session-control function are formally defined in full, to leverage investigation of its inner functionalities and expected behaviour on the system. The assessment of the functionalities is presented in order to highlight ambiguities that could lead to less secure implementations so as to provide for a more robust RBAC description that can cope with more rigid and predictable behaviour on Health Information Systems (HIS). Outcomes from poorly session-control implementation on a system include the inability to fulfil healthcare corporate security policy or even allowing illegal actions to take place due to the absence of expected restrictions and constraints imposed on user's interactions.

Deadlock Control and Fault Detection and Treatment in Reconfigurable Manufacturing Systems Using Colored Resource-Oriented Petri Nets Based on Neural Network

A reconfigurable manufacturing system (RMS) means that it can be reconfigured and become more complex during its operation. In RMSs, deadlocks may occur because of sharing of reliable or unreliable resources. Various deadlock control techniques are proposed for RMSs with reliable and unreliable resources. However, when the system is large-sized, the complexity of these techniques will increase. To overcome this problem, this paper develops a four-step deadlock control policy for the detection and treatment of faults in an RMS. In the first step, a colored resource-oriented timed Petri net (CROTPN) is designed for rapid and effective reconfiguration of the RMS without considering resource failures. In the second step, “sufficient and necessary conditions” for the liveness of a CROTPN are introduced to guarantee that the model is live. The third step considers the problems of failures of all resources in the CROTPN model and guarantees that the model is reliable by designing a common recovery subnet and adding it to the obtained CROTPN model at the second step. The fourth step designs a new hybrid method that combines the CROTPN with neural networks for fault detection and treatment. A simulation is performed using the GPenSIM tool to evaluate the proposed policy under the RMS configuration changes and the results are compared with the existing approaches in the literature. It is shown that the proposed approach can handle any complex RMS configurations, solve the deadlock problem in an RMS, and detect and treat failures. Furthermore, is simpler in its structure.

Colored Resource-Oriented Petri Nets for Deadlock Control and Reliability Design of Automated Manufacturing Systems

Reliability modeling and deadlock control have become important issues in automated manufacturing systems (AMSs) with reliable and unreliable resources. Therefore, this paper develops a reliability modelling approach and deadlock control based on colored resource-oriented timed Petri net (CROTPN) and neural networks to find crucial reliability measures in AMSs. In the first step, a CROTPN with considering resource failures is developed to obtain “sufficient and necessary conditions” for the CROTPN liveness. In the second step, a fault diagnosis and treatment approach is proposed that integrates the obtained unreliable net with neural networks to ensure that the system is reliable. Furthermore, a neural unreliable CROTPN is used to analyze the system reliability. A simulation is carried out to illustrate the approach and compare the results to those found in the literature. The developed approach has been proved to be simpler in structure and can solve the deadlock problem and model AMS reliability.

ВЕРИФИКАЦИЯ СИСТЕМ УПРАВЛЕНИЯ ДОСТУПОМ НА ОСНОВЕ МОДЕЛИРОВАНИЯ РАСКРАШЕННЫМИ СЕТЯМИ ПЕТРИ

Introduction: the complexity of the information systems (IS) being developed increases the requirements for the error-free design of the access control system and increases the likelihood of the presence and impact of vulnerabilities on the state of information security. Formal verification of the IS project at the development stage allows minimizing the appearance of architectural vulnerabilities. Changes carried out by regulators in the field of certification of information security means actualizing issues related to the development and analysis of formal models. Purpose: development of an approach to the construction and formal verification of models that has an intuitively, completeness presentation and effective analysis. Methods: construction of models by the mathematical apparatus of colored Petri nets in the CPN Tools modeling environment with the subsequent study of the properties of the net. Results: an approach has been developed that has structural, logical and dynamic completeness. The clarity of the models developed using the presented approach reduces the time for detecting incorrect functioning and developing compensatory measures with the subsequent confirmation of their effectiveness. The analyze of the state space showed the need to supplement the modeling environment for the complete construction of the state space in the case of complex models and a large number of markers during the initial marking of the Petri net. Practical relevance: the developed approach is proposed to be used for formal verification of access control models and filtering information flows in the certification procedure for information security tools. The versatility and simplicity of the approach allows you to implement the formal verification procedure in the development stages of various kinds of systems. Development prospects: development of additional software that allows building a complete state space for com" plex models, as well as complementing the method with approaches using ASK-CTL logic.

Simulation of single-phase ground short circuit protection device

The most common type of short circuit in a three-phase system is a single-phase-to-ground short circuit, accounting for 70 to 90% of electrical faults. In this paper simulation of the protective device from single-phase-to-ground short circuit with automatic change of current setting in electrical networks of 6-10 kV voltage on the basis of Coloured Petri Net is considered. The complexity of elaborated technical systems makes the problem of their modelling actual at the stage of development with the purpose of obtaining estimations of prospective and achievable characteristics. Now the modelling theory of the dynamic discrete systems, based on the formalism of Coloured Petri Nets has a wide application. Petri Net, describing the device operation, was designed and analysed using CPN Tools Programm. The resulting Petri net is correct, as it is live, reversible and safe. Thereby designed device can provide the selective protection from single-phase-to-ground short circuit.

Guaranteeing Correctness of Machine Learning Based Decision Making at Higher Educational Institutions

State-of-the-art software technologies have enabled Higher Education Institutions to record and store large amounts of student data. Analyzing this large amount of data can facilitate the decision-making process. Decisions made in higher education institutions affect policies, strategies and actions that improve education quality. It can be argued that machine learning algorithms demonstrate a remarkable ability to recognize models and predict results based on data. However, machine learning outcomes were subject to bias and erroneous labelling. Consequently, to mitigate the impact of such errors in decision making, it is necessary to put in place mechanisms to correct decision rules. This article presents an approach to learn decision rules through supervised machine learning and proves the correctness of these rules with hierarchical Coloured Petri Nets. The use of formalism in the proposed methodology ensures that the decision rules are correct and comprehensible. Empirical results show that we improved correctness with 98.68% accuracy on decision rules. This research work contributes to the improvement of the decision-making process for the academic administration of Higher Education Institutes.

Method of Performance Analysis of Time-Critical Applications Using DB-Nets

These days, most of time-critical business processes are performed using computer technologies. As an example, one can consider financial processes including trading on stock exchanges powered by electronic communication protocols such as the Financial Information eXchange (FIX) Protocol. One of the main challenges emerging with such processes concerns maintaining the best possible performance since any unspecified delay may cause a large financial loss or other damage. Therefore, performance analysis of time-critical systems and applications is required. In the current work, we develop a novel method for a performance analysis of time-critical applications based on the db-net formalism, which combines the ability of colored Petri nets to model a system control flow with the ability to model relational database states. This method allows to conduct a performance analysis for time-critical applications that work as transactional systems and have log messages which can be represented in the form of table records in a relational database. One of such applications is a FIX protocol-based trading communication system. This system is used in the work to demonstrate applicability of the proposed method for time-critical systems performance analysis. However, there are plenty of similar systems existing for different domains, and the method can also be applied for a performance analysis of these systems. The software prototype is developed for testing and demonstrating abilities of the method. This software prototype is based on an extension of Renew software tool, which is a reference net simulator. The testing input for the software prototype includes a test log with FIX messages, provided by a software developer of testing solutions for one of the global stock exchanges. An application of the method for quantitative analysis of maximum acceptable delay violations is presented. The developed method allows to conduct a performance analysis as a part of conformance checking of a considered system. The method can be used in further research in this domain as well as in testing the performance of real time-critical software systems.

Conversion and Verification of Business Processes from a BPMN Model to a Colored Petri Nets Model

Conversion and Verification of Business Processes from a BPMN Model to a Colored Petri Nets Model

Simulation and Improvement of Patients' Workflow in Heart Clinics during COVID-19 Pandemic Using Timed Coloured Petri Nets.

The COVID-19 epidemic has spread across the world within months and creates multiple challenges for healthcare providers. Patients with cardiovascular disease represent a vulnerable population when suffering from COVID-19. Most hospitals have been facing difficulties in the treatment of COVID-19 patients, and there is a need to minimise patient flow time so that staff health is less endangered, and more patients can be treated. This article shows how to use simulation techniques to prepare hospitals for a virus outbreak. The initial simulation of the current processes of the heart clinic first identified the bottlenecks. It confirmed that the current workflow is not optimal for COVID-19 patients; therefore, to reduce waiting time, three optimisation scenarios are proposed. In the best situation, the discrete-event simulation of the second scenario led to a 62.3% reduction in patient waiting time. This is one of the few studies that show how hospitals can use workflow modelling using timed coloured Petri nets to manage healthcare systems in practice. This technique would be valuable in these challenging times as the health of staff, and other patients are at risk from the nosocomial transmission.

Deep learning-based procedure compliance check system for nuclear power plant emergency operation

Operating procedures are strictly followed in nuclear power plant operation. However, under a highly stressful condition such as emergency operation, human error probability can increase, with operators making mistakes in complying with the complex operating procedures. This paper proposes a procedure compliance check (PCC) system to monitor operator action and detect procedural deviation. If an operator action does not match the related procedural instruction, the PCC system notifies the operator in order to help them to recognize the mistake. A procedural logic process is constructed by referring to colored Petri nets. In situations requiring complex decisions, the PCC system employs a deep learning algorithm to predict operator judgement. The system was tested with data from a compact nuclear simulator, and demonstrated its potential to detect procedural noncompliance.

MODELING OF INTELLECTUAL CONTROL SYSTEMS WITH APPLICATION OF MODIFIED FUZZY COLORED PETRI NETS

A modification of the Petri nets is proposed  a Fuzzy Colored Petri Net (FCPN), leading to the integration of Fuzzy Petri Nets (FPN) and Colored Petri Nets (CPN). Separately, the shortcomings of FPN and CPN and the advantages the developed FCPN for modeling intelligent control systems are identified and justified. In the developed modified FCPN the membership functions of the terms of a linguistic variable are applied to markers of the CPN as color and fuzzy existence conditions are assigned to arcs depending on the values of the linguistic variable. As a result, FCPN with enhanced capabilities was obtained, which eliminates the shortcomings of CPN and FPN. The FCPN and a simulation approach are defined, which includes a reasoning algorithm, as well as a detailed procedure for modeling and analysis of nonlinear discrete objects. The structure is organized in the CPN Tools system with the synchronization of the CPN ML (Markup Language) language with the MatLab package. The choice of membership function and fuzzification of term values is performed in the Fuzzy Toolbox application of the MatLab system. The proposed approach is illustrated by simple example, including the control of water pumps, to maintain the required water level in the pumping well. A model is developed for the automation of adaptive fuzzy control of water pumps based on modified FCPN. Based on the criteria for the operation of water pumps according to the water levels in the pumping well, many positions and transitions of the FCPN are formed. Describing the necessary behavior of the system by the relations between the positions and transitions of the FCPN using the logic “If ... Then ...” an adaptation algorithm is developed. Based on the algorithm, the matrices of input and output incidents are determined. The graph model of the FCPN is developed. Visualization of the model is implemented in the CPN Tools system. The computer simulations and net analysis experiments demonstrate the convenience of the developed approach when modeling the intelligent control of dynamic systems.

A Ubiquitous Machine Learning Accelerator With Automatic Parallelization on FPGA

Machine learning has been widely applied in various emerging data-intensive applications, and has to be optimized and accelerated by powerful engines to process very large scale data. Recently, the instruction set based accelerators on Field Progarmmable Gate Arrays (FPGAs) have been a promising topic for machine learning applications. The customized instructions can be further scheduled to achieve higher instruction-level parallelism. In this article, we design a ubiquitous accelerator with out-of-order automatic parallelization for large-scale data-intensive applications. The accelerator accommodates four representative applications, including clustering algorithms, deep neural networks, genome sequencing, and collaborative filtering. In order to improve the coarse-grained instruction-level parallelism, the accelerator employs an out-of-order scheduling method to enable parallel dataflow computation. We use Colored Petri Net (CPN) tools to analyze the dependences in the applications, and build a hardware prototype on the real FPGA platform. For cluster applications, the accelerator can support four different algorithms, including K-Means, SLINK, PAM, and DBSCAN. For collaborative filtering applications, it accommodates Tanimoto, euclidean, Cosine, and Pearson Correlation as Similarity metrics. For deep learning applications, we implement hardware accelerators for both training process and inference process. Finally, for genome sequencing, we design a hardware accelerator for the BWA-SW algorithm. Experimental results show that the accelerator architecture can reach up to 25X speedup against Intel processors with affordable hardware cost, insignificant power consumption, and high flexibility.

Transformation from AADL to Colored Petri Nets for Dynamic Reconfiguration Process

Although integrated modular avionics (IMA) provides many advantages such as the reduced weight and higher efficiency for system operations, safety problems in IMA dynamic reconfiguration process come up due to its complexity to analyze. Architecture Analysis and Design Language (AADL) has advantage to model for embedded systems. However, it is quite limited to employ AADL for analyzing system safety. This paper, seeks to translate the AADL models of IMA dynamic reconfiguration process into colored petri net (CPN), which have advantages to simulate and evaluate embedded systems. Then, the colored petri net (CPN) is proposed for the analysis for AADL models, because CPN can describe the properties and behaviors of dynamic reconfiguration process well. Moreover, it is essential to make a transformation from the AADL models to the CPN models. This work will benefit the subsequent analysis of IMA dynamic reconfiguration process. Finally, a case study is provided for effectiveness the transformation rules.