State space analysis on an AI problem with CPN model

This paper describes model transformation for analyzing dynamic behavior of large-scale systems. The Unified Modeling Language (UML) based system model is transformed into the Colored Petri Nets (CPN) model, which is used for analyzing the scenarios of the use cases of a system and checking freedom of system deadlock at an early stage of software development. The CPN model that is executable is hierarchically structured on the basis of the functional decomposition of a large-scale system. The UML-based system model consisting of the use case model, class model and collaboration model is not executable so that the dynamic behavior of the system cannot be analyzed until implementation of the system. However, the UML-based system model has no hierarchical structure to be transformed into the hierarchical CPN model as well. The discrepancies of dynamic and structural views in the two models are resolved by transformation of the UML model into the layered, executable CPN model with three layers — the use case layer, object layer and operation layer. The model transformation is carried out using relationships among the use case model, class model, and collaboration model of the UML. With the executable CPN model transformed, the dynamic properties of the system are analyzed using the simulation technique, occurrence graph, and state space report provided by the Design/CPN tool. The approach in this paper is validated through two case studies — the gas station system and the distributed factory automation system.

Petri Nets provide a graphical notation for modeling systems and performing analysis. Colored Petri Nets (CPNs) combine the strengths of ordinary Petri Nets with a high level programming language, making them more suitable for modeling large systems. A CPN model is an executable representation of a system that can be analyzed through simulation. CPN models are built using CPN Tools, a graphical software tool and interface used to create, edit, simulate, and analyze models. This tutorial is meant to introduce the reader to the vocabulary and constructs of CPNs and illustrate the use of CPN Tools in creating and simulating models by means of a familiar, simple example. In particular, we show how to create a CPN model of the call center example presented by White and Ingalls in their tutorial Introduction to Simulation.

PurposeA major factor to the success of flexible manufacturing systems (FMSs) is their ability to transport work pieces between different workstations. FMS have now become more advanced and material‐handling systems have become progressively more sophisticated, it is not exceptional to have automated steering of tools to workstations as well. Such system design will improve the tool‐handling capability and the system productivity while holding tool cost to a minimum. Tool cost could represent as much as 25 percent of the operating cost. The purpose of this paper is to propose a new colored Petri net (CPN)‐based approach to the design and development of a tool sharing control system that is intended to help use of the proper and minimal number of tools for a manufacturing system.Design/methodology/approachA new black token timed PN model is first developed, to reduce the complexity of the graphical representation a new CPN model is developed. The new CPN model also allows to find the optimal sequence. The optimal sequence has no effect on the work in process (WIP) but it influences the number of tools used in the system. The main input to the PN model for a manufacturing system is the process plan. Next, all the invariants and total number of possible elementary circuits are determined using the Integrated Net Analyzer (INA) software. Output from the INA software is exported to the Excel spreadsheet. The Excel spreadsheet can be designed to calculate the total number of tokens, processing time, cycle time, etc. of each elementary circuit. Subsequently, the constraints used in Lingo will be created according to critical circuit rules. Finally, linear programming (LP) technique is used to optimize the WIP and tool inventory. Lingo software is used for the LP, the constraints from the Excel sheet will be the input data to the Lingo program, and based on those constraints the Lingo will provide the optimal values for the desired parameters. The output from Lingo will be used to recalculate the cycle time of each elementary circuit in the Excel sheet. The system is then analyzed before and after the implementation of the CPN model.FindingsA new CPN model based on tool‐sharing philosophy for an FMS with N part types and M stations is proposed.Originality/valueThe paper presents a new CPN‐based approach to the design and development of a tool sharing control system, that is, intended to help use of the proper and minimal number of tools for a manufacturing system. The new CPN model also allows to find the optimal sequence. The idea is new and pure and has not been presented before using the methodology adopted in this paper.

Security verification and performance analysis are both crucial aspects for designing effective and efficient authentication protocols. However, in most authentication protocol design practice, two independent models are often adopted for individual security verification and performance analysis, which could not guarantee that performance improvements taking no harm to its security functionalities. In this paper, a colored Petri nets (CPN) model based method is well utilized to integrate security verification and performance analysis for authentication protocols. The main idea is that the functional CPN model for an authentication protocol is constructed firstly for its security verification, and then performance related temporal constrains are added into above model to form a corresponding performance CPN model for simulation based performance evaluation towards that authentication protocol. Because such closely related CPN models are utilized where occurrence sequences existed in performance models are also behavior-equally existed in functional models, it is guaranteed that both models satisfy the security requirements for the authentication protocol. We present the security and performance joint analysis process of TRDP protocol, a representative example of authentication protocols, to illustrate the effectiveness of above CPN based integrated approach.

In a distributed embedded system, it is often necessary to share variables among its computing nodes to allow the distribution of control algorithms. It is therefore necessary to include a component in each node that provides the service of variable sharing. For that type of component, this paper discusses how to create a Colored Petri Nets (CPN) model that formally expresses the following elements in a clearly separated structure: (1) assumptions about the behavior of the environment of the component, (2) real-time requirements for the component, and (3) a possible solution in terms of an algorithm for the component. The CPN model can be used to validate the environment assumptions and the requirements. The validation is performed by execution of the model during which traces of events and states are automatically generated and evaluated against the requirements.

The Petri net (PN) formalism is a suitable tool for modeling parallel systems due to its basic characteristics, such as synchronization. The extension of PN, the Colored Petri Nets (CPN) allows the incorporation of more details of the real system into the model (for example, contention for shared resources). The CPNs have been widely used in a variety of fields to produce suitable models. One of their biggest strengths is that their overall philosophy is quite similar to the philosophy of the object-oriented paradigm. In this regard, the CPN models can be used to implement simulators in a rather straightforward way. In this paper, the CPN framework is employed to implement a new resource allocation simulator, which is used to verify the performance of our previous work, where we proposed a fair resource allocation scheme with flow control and maximum utilization of the system’s resources.

Web applications are main applications in Internet. Before developing Web Application, a CPN (Colored Petri net) model based on workflow is constructed. By this way, the rationality of the workflow can be ensured before developing, rather than the irrationality is found during testing phases. The constructed CPN model is analyzed with CPN tools. Moreover, AGTS tool is implemented to generate test sequences and it is also suitable for all CPN models. To prove the method's efficiency, the make-order business process of logistics management system is used as an example to construct CPN model that is based on workflow, and then verify the correction of the constructed CPN model. At the same time, AGTS tool can automatically generate the test sequences of the constructed CPN model and its usability of this automatic tool is demonstrated.

Information services play a crucial role in grid computing environments in that the state information of a grid system can be used to facilitate the discovery of resources and services available to meet user requirements and help tune the performance of the grid. This article models PIndex, which is a grouped peer-to-peer network with Colored Petri Nets (CPNs) for scalable grid information services. Based on the CPN model, a simulator is implemented for PIndex simulation and performance evaluation. The correctness of the simulator is further verified by comparing the results computed from the CPN model with the results generated by the PIndex simulator.

The context of our work is the complex systems simulation. Complex systems modelling and simulation require to take into account the interactions between the different components. For instance, an airport ground traffic simulation requires to model the planes with the pilots, the control tower, the

Matlab/Simulink is an industrial tool that is widely used to design and validate control algorithms for embedded control systems using numerical simulation. A Simulink model of a control system typically defines one or more control algorithms together with their environment. Such models exhibit both discrete and continuous dynamics, simulated by discretizing time. On the other hand, a colored Petri net (CPN) is a well known formalism for modeling behavior of discrete event systems. In this paper, we give a formal semantics to Simulink using the CPN formalism, by describing how Simulink models can be expressed as a CPN.We also show how Petri nets can be simulated in Simulink. Finally, we show how a CPN model can be used for performance analysis of a Simulink model.

Nowadays parallel software system is very common and practical. However, it is difficult to test parallel software, because the state space of parallel software is very large. Therefore, a parallel model simplification method based on CPN (Color Petri Net) is proposed. Based on the original CPN, the CPN model for the tested behavior(Tested Behavior of CPN, TBoCPN) is proposed. The target of the test is described as the tested behavior. The relevant behavior is described as the behavior related to the tested behavior, then, the homogeneous concurrent branch group and the selection branch set are divided. Finally, the branches of the concurrent branch group and the selected branch set, which satisfied the condition of algorithm, are sequentially processed by the inhibitor arcs. The experiment shows that the reduction rate is at least 60%, and before and after the reduction, the full coverage test path generated by the tested behavior is not affected, thus proving that the method is an effective test method.

The BPMN design models are widely used in the software development process. Owing to the lack of BPMN standard semantics, formal verification is used to validate whether the BPMN design model is free of undesirable properties. The primary challenges of BPMN design model verification are the enormous size and complexity of BPMN design models; these challenges may lead to time-consuming processes for model abstraction and overcoming the state space explosion problem. This paper proposes a hierarchical verification technique for the state space analysis based on a colored Petri net (CPN). A BPMN partitioning technique and rules for the transformation of a BPMN into a CPN model are provided. The partitioning approach supports the unstructured BPMN design model, and the obtained CPN model also supports hierarchical verification. To validate and analyze the BPMN design model, the transformation technique and state space generator are implemented as a BPMN verification framework. This method is a viable option for the software process designers and is suitable for the large-scale BPMN design model verification.

An integrated quantitative reconfiguration model for interacting satellite networks is a powerful tool in analyzing reliability and developing protocols for uninterrupted operation. However, such a model is not easy to develop since it involves many parameters related to the network’s operation including all the earth-linked communications. The aim of this study is to propose an integrated communication model for a network of interacting satellites using high level Petri Nets which permits sub-network reconfiguration without loss of communication whenever there are satellite faults. To model the communication interactions in a network of satellites, Colored Petri Nets (CPN) paradigm is used so as to simulate the operation of the integrated Networked Control System (NCS). A modular representation of the interacting satellites within the network in terms of senders and receivers including packet-data transmission through the network is provided. The packets stored on-board the satellites are sent via the network to the earth station which may not arrive successfully in case of a fault in the communication payload/network. The proposed approach is used to study the overall response time of a given NCS in interacting satellites, as well as the delays between the mutual senders and receivers. Simulations of the detailed model used show that the networked control performance of the interacting satellites, in particular with reference to any satellite failure, can be improved with inclusion of appropriate monitors within the networked system as represented by sub-networks in the CPN model. The proposed integrated networked control can be used to obtain a fault tolerant reconfiguration for a standard network performance.

Workflow model is useful for representing the activities of work process in business, but there are no tools to analyze and emulate it. In this paper, a series of rules are given which can map the ordinary workflow model into Colored Petri net (CPN) model, which is executable and analyzable in the CPN Tools environment. Some characteristics of the workflow, such as roles, activities, sub-processes, resources and other basic elements are represented with tokens, transitions, substitution transitions, places in the CPN respectively. Some basic structure elements (Sequence, and branches, and connection, or branches, or connections, selection branches) and basic control structures (Sequence structure, parallel structure, single choice, simple merge, cycle, multiple choice, multiple merge)are transformed into CPN models according to the rules given in this paper.

This thesis proposal suggests a model-based approach to obtain, from a set of behavioural scenarios of a given reactive software system, a graphical animation for reproducing that set of scenarios for validation purposes. The approach assumes that the requirements of the system are described by a use case diagram, being the behaviour of each use case detailed by a collection of scenario descriptions. These use cases and scenarios are transformed into a Coloured Petri Net (CPN) model, which is next complemented with animation-specific elements. By executing the CPN model, it is possible to animate the scenarios in a user-friendly way and thus ensuring an effective involvement of the users in the system's validation. The CPN model is enforced to be (1) parametric, allowing an easy modification of the initial conditions of the scenarios, (2) environment-descriptive, meaning that it includes the state of the relevant elements of the environment, and (3) animation-separated, implying that the elements related to animation are clearly separated from the other ones. We validate our approach based on its application to two examples of reactive systems.