Colored Petri Net

When an organization's output declines due to either internal changes or changes in its external environment, it needs to adapt. In order to evaluate the effectiveness of different adaptation strategies on organizational per- formance, an organizational model composed of individual models of a five stage interacting decision maker was designed using an object oriented design approach and implemented as a

Object oriented analysis and design can be applied to the problem of organizational design and the Colored Petri Net formalism, while the supporting software can be used effectively to implement the approach. Furthermore, existing results can be mapped easily in this paradigm. A dynamical model representation of the organization is obtained that can be analyzed using both Petri Net theory and the associated algorithms, as well as simulation.

Types of variable structure decision making organizations are defined and triggers of adaptation are discussed. An approach to determining quasi-static organizational forms is described; in this approach a set of fixed structure organizational forms are used. Then, an algorithm for determining incrementally adapting organizations is outlined. This includes the representation of the adaptive structures, the set of rules that govern the adaptation, and the determination of the feasible paths through which a given structure can be transformed to another one. The procedure establishes requirements for the underlying command, control, and communications system.

Industry 4.0 is a key strategic trend of the economy. Virtual factories are key building blocks for Industry 4.0 where product design processes, manufacturing processes and general collaborative business processes across factories and enterprises are integrated. In the context of EU H2020 FIRST (vF Interoperation suppoRting buSiness innovaTion) project, end users of vFs are not experts in business process modelling to guarantee correct collaborative business processes for realizing execution. To enable automatic execution of business processes, verification is an important step at the business process design stage to avoid errors at runtime. Research in business process model verification has yielded a plethora of approaches in form of languages and tools that are based on Petri nets family and temporal logic. However, no report specifically targets and presents a comparative assessment of these approaches based on criteria as one we propose. In this paper we present an assessment of the most common verification approaches based on their expressibility, flexibility, suitability and complexity. We also look at how big data impacts the business process verification approach in a data-rich world.

The coordination of interdependencies among activities in collaborative environments is a very important and difficult task. In this paper we present a set of coordination mechanisms for the specification and control of interaction among collaborative activities. To model these mechanisms, we use high level Petri nets, which have proven to be an adequate approach to evaluate the behavior of a computer supported collaborative system before its implementation.

Objetos de Aprendizagem (OAs) são recursos digitais desenvolvidos para serem utilizados dentro do contexto educacional como ferramenta de apoio ao processo de aquisição de conhecimento do indivíduo. Tais recursos, evidenciados no Brasil por esforços como o do RIVED (Rede Interativa Virtual de Educação), têm mostrado a importância dos OAs, e, particularmente, das simulações e animações, como artefatos de software capazes de auxiliar a prática pedagógica. Contudo, em virtude do grau de complexidade dos requisitos envolvidos na produção desses artefatos, há a necessidade de se contar com diferentes tipos de profissionais, que possam responder, de forma coerente, pelo caráter tanto pedagógico quanto técnico. Entretanto, esse caráter multidisciplinar afeta o processo de desenvolvimento em virtude das imprecisões na comunicação dos diferentes tipos de requisitos entre esses profissionais. Nesse sentido, propomos nesse trabalho, a adoção de um modelo formal, denominado LOCPN (Learning Objects production with Colored Petri Nets), desenvolvido especificamente para auxiliar o processo de desenvolvimento de OAs. A eficácia da utilização de LOCPN é comprovada neste trabalho pela qualidade das implementações e pela redução significativa do tempo de produção de OAs.

Understanding the operations of a large "net-centric system-of-systems" requires in-depth knowledge of the interfaces and the interactions among the various systems, subsystems, and components. Architectural modeling can help in reducing the complexity involved in designing large networked systems. This paper demonstrates a modeling approach for network centric systems. An example of such a complex system is the Global Earth Observation System of Systems (GEOSS)-a system for monitoring and collecting information related to Earth's resources. The GEOSS is an evolving complex network centric system. The modeling of the GEOSS has been demonstrated using the Systems Modeling Language (SysML). In this paper,

In this paper we study the problem of deadlock avoidance of production lines with shared resources. We use the Petri net model for production lines and a restrictive policy which prevents some enabled transition from firing for avoiding deadlock in the system. This is the safety control for non-stochastic discrete event systems. We generalise this notion of safety to the setting of stochastic discrete event systems, modelled as Markov chains. We propose a restriction policy for this generalised case.

This paper presents a project methodology applied to reconfigurable processes in the context of agile manufacturing systems. The proposal methodology consists of a cyclic three-stage development -modeling, synthesis and implementation -until the real system accomplishes the required application, resulting in the project of the automated and integrated system. The present paper details the three stages and describes which steps must be executed on each one of it. Also, the mathematical formalism used in methodology is presented, as a basis for implementation of reconfigurable processes. To submit to a test and validate the proposal approach, the methodology is applied to a manufacturing system's prototype. In the experiment, it is considered that 2 products must be manufactured in different times, demanding the processes can be reconfigurable in a fast and reliable way.

This paper presents an implementation environment applied to reconfigurable processes in automated manufacturing systems. This environment is based on a methodology which consists of a cyclic three-stage development -modeling, synthesis and implementation -until the real system accomplishes the required specification, resulting in the project of the automated system. This kind of development allows a continuous result revision of each stage. The present paper describes the methodology and details of components of the proposed environment.

In this work we address the issue of selecting and composing Web Services (WSs) considering functional requirements and transactional properties. We formalize the WS composition problem using the user query, the transactional properties of WSs and the composite WSs definition. We extends Colored Petri Net (CPN) formalism to incorporate transactional WSs properties. We present a CPN-WS selection algorithm that satisfies the user query functional conditions expressed as input and output attributes, and transactional properties expressed as a risk level. The result of our algorithm is a Colored Petri-Net allowing to execute a transactional composite WS.

To manage a complex system, an operation model is proposed for evaluating the effectiveness and efficiency of each possible plan. During the planning process, an easy-to-use modeling system for operation modeling could be very useful for assisting the shop floor manager to understand and predict the performance of operation plans. In this paper, the Petri Net is used as a tool to realize the proposed modeling concept. Derived from the basic Colored Petri Net (CPN) language, a Modular Colored Petri Net (MCPN), composed of a number of CPN Modules (CPNMs), is proposed for this adaptive modeling approach. The CPN in each CPNM represents the discrete event logic of the corresponding operation. Despatching rules of the material and activities are modeled by the components and functions of the CPNs in these CPNMs, and the dynamics of the system can be modeled by the transition firing and connections amongst them. In this way, the time and cost for the development and maintenance of the shop floor operation model can be reduced. The application of the system in in-process control in a plastic processing plant is illustrated in the paper.

In this work we introduce a new formal model for software components supporting behavioral interpretability based on temporal logic, Petri nets, model checking, and an assume-guarantee strategy to specify and reason about the composition of concurrent component systems. The formal specification and verification strategies, methods, and techniques presented in this work contribute to the development of more dependable component-based software systems, in a modular way. An approach based on two complementary formalisms, Hierarchical Colored Petri Nets (HCPN) and temporal logic, is introduced. HCPN are used to visualize the structure and model the behavior of software architectures and components, and temporal logic is used to specify the required properties of software architectures and component interfaces.

A workflow management system (WfMS) provides a central control point for defining business processes and orchestrating their execution. A major limitation of current WfMSs is their lack of support for dynamic workflow adaptations. This functionality is an important requirement in order to provide sufficient flexibility to cope with expected but unusual situations and failures. In this paper, we propose Self-Adaptive Recovery Net (SARN), an extended Petri net model for specifying exceptional behavior in workflow systems at design time. SARN can adapt the structure of the underlying Petri net at run time to handle exceptions while keeping the Petri net design simple and easy. The proposed framework also caters for high-level recovery policies that are incorporated either with a single task or a set of tasks, called a recovery region.

In this work we present a model for the development of Learning Objects. The model was constructed and evaluated using Coloured Petri Nets, and the results presented in this article. The adoption of model allows the specification and analysis of the flow of production as well as sizing of team and identification of bottlenecks in production in general. Resumo. Neste trabalho apresentamos um modelo para o desenvolvimento de Objetos de Aprendizagem Acessíveis. O modelo foi construído e avaliado por Redes de Petri Coloridas, e os resultados apresentados neste artigo. A adoção do modelo permite a especificação e análise do fluxo de atividades da produção dos conteúdos, bem como dimensionamento da equipe e identificação de gargalos na produção em geral.

As redes de Petri (RPs) constituem-se em uma ferramenta matemática e gráfica de uso geral. Sugere-se, neste trabalho, o uso de RPs como uma ferramenta de modelagem voltada para o ensino de noções matemáticas. A modelagem apoia-se no fato de as RPs terem como característica a representação de sistemas que utilizam forte base matemática. Como estudo de caso, apresenta-se uma modelagem para a organização do conteúdo de ensino sobre integrabilidade de funções reais baseada na evolução do conceito de integral. Para isto, considera-se uma função limitada, definida em um intervalo fechado e limitado da reta, que é analisada relativamente a condições que garantam ou excluam a sua integrabilidade por Cauchy, por Riemann, por Lebesgue ou por nenhum destes. A ideia de se modelar este conceito por RPs originou-se no contexto da sala de aula, por ocasião de seu ensino a alunos de primeiro ano de engenharia.

In this Paper, a viable analysis and implementation of local modular Supervisory Control Theory for a manufacturing cell is predicted in the best possible manners to capture the necessities of idealizing the programmable logic controller (PLC). By means of local modular approach a methodology that reveals modularity of the plant and of the behavioral specifications models optimal supervisors are obtained without state-space explosion. For the purpose of simplifying the ladder diagram implementation in the PLC, reduced supervisors are implemented in a three level structure that executes the modular supervisor’s concurrent action and interfaces the theoretical model with the real system. The flexible and productive manufacturing cell behavior, after the control system practical implementation, and the final PLC code readability and flexibility are positive quality indicators to the applied methodology.

Industry currently employs a product line approach to software development and deployment as a means to enhance quality while reducing development cost and time. This effort has created a climate where safety-critical software product lines are being developed without the full range of accompanying safety analysis tools available to software engineers. Software Fault Tree Analysis (SFTA) is a technique that has been used successfully to investigate contributing causes to potential hazards in safety-critical applications. This paper further extends the adaptation of SFTA to product lines of systems by describing a software safety analysis tool called PLFaultCAT. PLFaultCAT is an interactive, partially-automated support tool to aid software engineers in the application of product-line software SFTA. The paper describes the integration of product-line SFTA and PLFaultCAT with the software development life cycle. The description includes the initial construction of the product-line SFTA as well as the automated derivation of software fault trees for product line members. The technique and tool are illustrated with a small case study throughout the paper.

Resumo: Algumas políticas públicas têm impulsionado o desenvolvimento de material digital para uso como recurso no processo de ensino e aprendizagem, incentivando o surgimento de várias equipes, cujos produtos desenvolvidos tendem a se concentrar em repositórios para que sejam acessíveis ao público-alvo. Muitas vezes o entendimento de quais elementos devem estar presentes num objeto varia entre as equipes, dificultando sua estruturação, recuperação e reuso. Este artigo analisa essas dificuldades no âmbito de ...

Рассматриваются спецификации распределенных систем на языке Dynamic-REAL (dREAL) с динамическим порождением и уничтожением экземпляров процессов. В качестве сетевой модели выбраны модифицированные раскрашенные сети Петрииерархические временные типизированные сети (ИВТ-сети), в которых используются приоритеты, специальные места, представляющие очереди фишек, и концепция интервального времени. Предложен метод трансляции языка dREAL в ИВТ-сети. На основе этого метода реализован транслятор из языка dREAL в эту сетевую модель. Ключевые слова: распределенные системы, язык Dynamic-REAL, раскрашенные сети Петри, иерархические временные типизированные сети, метод трансляции.

A model-based agent system model for medicine usage management is presented and formally analysed. The model incorporates an intelligent ambient agent model that has an explicit representation of a dynamical system model to estimate the medicine level in the patient's body by simulation, is able to analyse whether the patient intends to take the medicine too early or too late, and can take measures to prevent this.

Creating new modeling environments has become a relatively low-cost investment thanks to meta modeling environments and language workbenches that can automatically synthesize environments from language specifications. However, the currently existing tools are focused on language syntax and execution/simulation rather than providing means to reason with semantic properties from the real world. It appears that reasoning opportunities as they arise in ontology research (e.g., based on description logics) are currently not exploited in the field of language engineering. In this vision paper, we explore the integration of the hitherto rather isolated areas of language engineering and ontology engineering in order to exploit the potential of using reasoning for models expressed in user-defined languages.

and distributed, our design methods and techniques must evolve to better explore these new directions. This paper reports on “Layered Elaboration, ” a co-design technique created to support these evolving needs. Layered Elaboration allows design teams to generate ideas through an iterative process in which each version leaves prior ideas intact while extending concepts. Layered Elaboration is a useful technique as it enables co-design to take place asynchronously and does not require much space or many resources. THE FOUNDATIONS OF LAYERED ELABORATION The concept for Layered Elaboration has its roots in storyboarding for interactive media [5], paper prototyping [8], and annotation tools [6]. Storyboards and drawings have been used as a method in participatory design research

Static analysis techniques for consistency checking of workflows allow to avoid runtime errors. This is in particular crucial for long running workflows where errors, detected late, can cause high costs. We consider workflows in which the processed data has semantic metadata in terms of a given domain ontology, like e.g. for medical trials. Such semantic metadata is not only crucial to allow data integration, but can also help to improve data quality. In our work we show that it can be utilized in static analysis techniques to detect data inconsistencies in the workflow definition at design time of the workflow. We divide data inconsistencies into two categories:

We propose an IDE-Integrated Development Environment to model SBVR (Semantic of Business Vocabulary and Business Rule) compliant business rules [2] extracted from business contract of services and store them in an ontological structure of rules, facts and terms as defined in the SBVR metamodel. Business rules are based on principles of deontic logic for treating expressions in the form of normative policies. Deontic constraints express what parties to the contract are required to perform (obligations), what they are allowed to do (permissions), or what they are not allowed to do (prohibitions).

As supply chains become more dynamic, it is important to be able to model them formally as business processes. In particular, there is a need for a sense-and-respond capability to react to events in a real-time manner. In this paper, we propose Petri nets extended with time and color (case data) as a formalism for doing so. Hence, we describe seven basic patterns that are used to capture modeling concepts that arise commonly in supply chains. These basic patterns may be used by themselves and also combined to create new patterns. Next, we show how to combine the patterns to build a complete Petri net and analyze it using dependency graphs and simulation. Dependency graphs can be used to analyze the various events and their causes. Simulation was, in addition, used to analyze various performance indicators (e.g., fill rates, replenishment times, and lead times) under different strategies. We showed it is possible to performed sensitivity analysis to study the effect of changing parameter values on the performance indicators. This approach thus makes a very complex problem tractable.

Database administrators need to compute closure of functional dependencies (FDs) for normalization of database systems and enforcing integrity rules. Colored Petri net (CPN) is a powerful formal method for modelling and verification of various systems. In this paper, we modelled Armstrong's axioms for automatic proof generation of a new FD rule from initial FD rules using CPN. For this purpose, a CPN model of Armstrong's axioms presents and initial FDs considered in the model as initial color set. Then we search required FD in the state space of the model via model checking. If it exists in the state space, then a recursive ML code extracts the proof of this FD rule using further searches in the state space of the model.

Objetos de Aprendizagem (OAs) são recursos digitais desenvolvidos para serem utilizados dentro do contexto educacional como ferramenta de apoio ao processo de aquisição de conhecimento do indivíduo. Tais recursos, evidenciados no Brasil por esforços como o do RIVED (Rede Interativa Virtual de Educação), têm mostrado a importância dos OAs, e, particularmente, das simulações e animações, como artefatos de software capazes de auxiliar a prática pedagógica. Contudo, em virtude do grau de complexidade dos requisitos envolvidos na produção desses artefatos, há a necessidade de se contar com diferentes tipos de profissionais, que possam responder, de forma coerente, pelo caráter tanto pedagógico quanto técnico. Entretanto, esse caráter multidisciplinar afeta o processo de desenvolvimento em virtude das imprecisões na comunicação dos diferentes tipos de requisitos entre esses profissionais. Nesse sentido, propomos nesse trabalho, a adoção de um modelo formal, denominado LOCPN (Learning Objects production with Colored Petri Nets), desenvolvido especificamente para auxiliar o processo de desenvolvimento de OAs. A eficácia da utilização de LOCPN é comprovada neste trabalho pela qualidade das implementações e pela redução significativa do tempo de produção de OAs.

World Wide Web is developing in a chaotic and unfocused process, and this process has resulted in production of documents which are linked with each other, and which are not logically organized. Therefore, the aim of recommender systems is guiding users to find their favorite resources and meet their needs, by using the information obtained from the previous users ’ interactions. In this paper, to predict the users’ navigation pattern with high precision, a hybrid algorithm of FCM fuzzy clustering techniques, weighted association rules, and fuzzy systems are presented. This algorithm is implemented in two phases, namely offline and online phases. In offline phase, using the recorded data in log file of the web server, the users ’ navigation patterns are extracted. In online phase, the recommender system suggests, as the initial proposed set, a list of the current user’s favorite webpages which he/she has not visited yet. Then it expands this set using HITS algorithm so that the new ...

Technology is, now, looking for distributed applications to develop and increase its domains. Web services are distributed components that provide functionality applications through network. They can be used by applications written in different languages, and performed in different platforms on different systems. The concept of Web services is essentially based on standard internet protocols, such as UDDI (Universal Description, Discovery and Integration), WSDL (Web Service Description Language) and SOAP (Simple Object Access Protocol) which offer solutions for description, publication, discovery, and interoperability of Web services. However, the complex composition of Web services is not guaranteed by them, therefore, different approaches have been proposed to solve this problem. Current Web services composition approaches range from practical languages aspiring to become standard like Business Process Execution Language (BPEL) to theoretical model like Petri nets. In this paper, ...

As supply chains become more dynamic, it is important to be able to model them formally as business processes. In particular, there is a need for a sense-and-respond capability to react to events in a real-time manner. In this paper, we propose Petri nets extended with time and color (case data) as a formalism for doing so. Hence, we describe seven basic patterns that are used to capture modeling concepts that arise commonly in supply chains. These basic patterns may be used by themselves and also combined to create new patterns. Next, we show how to combine the patterns to build a complete Petri net and analyze it using dependency graphs and simulation. Dependency graphs can be used to analyze the various events and their causes. Simulation was, in addition, used to analyze various performance indicators (e.g., fill rates, replenishment times, and lead times) under different strategies. We showed it is possible to performed sensitivity analysis to study the effect of changing parameter values on the performance indicators. This approach thus makes a very complex problem tractable.

In this paper a software production methodology for process control is presented. The specification phase is carri e d out by resorting to the formalism of Petri Nets. By means of a worked example it is shown how Petri Nets are amenable to describe feedback control structures. The implementation of Petri Net models is performed by the use of a data driven architecture. The presence of system tasks supplying standard functions, such as monitor, display, command acquisition is also considered to ease software production.

The broadcast storm problem causes redundancy, contention and collision of messages in a network, particularly in vehicular ad hoc networks (VANETs) where number of participants can grow arbitrarily. This paper presents a solution to this problem in which a node is designated as a master through an election process. Moreover, an algorithm is proposed for asynchronous VANETs to select a master node, where the participants (i.e., vehicles) can communicate with each other directly (single-hop). The proposed algorithm is extrema-finding in a way that a node having maximum signal strength is elected as a master node and each vehicle continues communication with the master until the master node keeps its signal strength at the highest level and remains operational too. This paper further presents the Petri net-based modeling of the proposed algorithm for evaluation which is going to be presented for the first time in leader election algorithm in VANETs. Verification of the proposed algorithm is carried out through state space analysis technique.

In wireless network research, simulation is the most imperative technique to investigate the network's behavior and validation. Wireless networks typically consist of mobile hosts; therefore, the degree of validation is influenced by the underlying mobility model, and synthetic models are implemented in simulators because real life traces are not widely available. In wireless communications, mobility is an integral part while the key role of a mobility model is to mimic the real life traveling patterns to study. The performance of routing protocols and mobility management strategies e.g. paging, registration and handoff is highly dependent to the selected mobility model. In this paper, we devise and evaluate the Show Home and Exclusive Regions (SHER), a novel two-dimensional (2-D) Colored Petri net (CPN) based formal random mobility model, which exhibits sociological behavior of a user. The model captures hotspots where a user frequently visits and spends time. Our solution eliminates six key issues of the random mobility models, i.e., sudden stops, memoryless movements, border effect, temporal dependency of velocity, pause time dependency, and speed decay in a single model. The proposed model is able to predict the future location of a mobile user and ultimately improves the performance of wireless communication networks. The model follows a uniform nodal distribution and is a mini simulator, which exhibits interesting mobility patterns. The model is also helpful to those who are not familiar with the formal modeling, and users can extract meaningful information with a single mouse-click. It is noteworthy that capturing dynamic mobility patterns through CPN is the most challenging and virulent activity of the presented research. Statistical and reachability analysis techniques are presented to elucidate and validate the performance of our proposed mobility model. The state space methods allow us to algorithmically derive the system behavior and rectify the errors of our proposed model.

The wireless mesh network (WMN) is an emerging and cost-effective alternative paradigm for the next generation wireless networks in many diverse applications. In the performance evaluation of routing protocol for the WMN, it is essential that it should be evaluated under realistic conditions. The usefulness of specific mobility protocol can be determined by selection of mobility model. This paper introduces a coloured Petri nets (CP-nets) based formal model for implementation, simulation, and analysis of most widely used random waypoint (RWP) mobility model for WMNs. The formal semantics of hierarchical timed CP-nets allow us to investigate the terminating behavior of the transitions using state space analysis techniques. The proposed implementation improves the RWP mobility model by removing the “border effect” and resolves the “speed decay” problem.

The rate is assessed as per the body fat percentages (%BF) estimated through anthropometric measurements and manual bioimpedance, according to gender and adiposity rate within the paediatric population. The %BF is assessed by anthropometry using the Slaughter equation for cutaneous skinfolds and manual bioimpedance (Omron model HBF-306INTTM) to 321 students (160 females and 161 males) between 10-18 years. The association degree among the methods was measured using the Pearson correlation coefficient (r). The consistency among methods was analysed through the intra-class correlation coefficient (ICC) and the consistency correlation coefficient of Lin (CCC), grouping the population by gender and adiposity rate. The reference method was the cutaneous skinfolds assessed by the Slaughter equation. Optimum and high adiposity rates were recorded for the studied sample. The r between the bioimpedance and the anthropometry was 0.689, which corresponds to moderate. However, it decreased according to the gender and adiposity rate (females: optimum 0.409 and high 0.610; males: optimum 0.335 and high 0.507). The ICC was 0.668, which also decreased by gender and adiposity rate (females: optimum 0.323 and high 0.578; males: optimum 0.229 and high 0.506). CCC was poor (<0.90) by gender and adiposity rate. The study shows differences for both methods in this age range, which is accentuated by gender and adiposity rate. Therefore, the use of manual bioimpedance as an interchangeable method with the anthropometric measurements in children and adolescents is not suggested as it underestimates the %BF.

In the current military operating environment, cordon and search missions (village searches) are conducted daily. It is expected that this mission profile will not change in the near future. Despite the frequency of this mission type, the planning tools available to military leaders are rudimentary and tedious. Planners must rely on oversimplified data tables and personal experience when planning a cordon and search. Computer tools to facilitate faster, more accurate plans do not yet exist. This paper proposes a timed, stochastic Petri Net model for cordon and search missions that can provide planners valuable mission insight using Monte Carlo simulation methods. This model can be used by military leaders to make robust decisions during mission planning and thus improve the quality of the final plan. 

In the current military operating environment, cordon and search missions (village searches) are conducted daily. It is expected that this mission profile will not change in the near future. Despite the frequency of this mission type, the planning tools available to military leaders are rudimentary and tedious. Planners must rely on oversimplified data tables and personal experience when planning a cordon and search. Computer tools to facilitate faster, more accurate plans do not yet exist. This paper proposes a timed, stochastic Petri Net model for cordon and search missions that can provide planners valuable mission insight using Monte Carlo simulation methods. This model can be used by military leaders to make robust decisions during mission planning and thus improve the quality of the final plan. 

This paper deals with a formal method for the study of the backward reachability analysis applied on Colored Petri Nets (CPN). The proposed method proceeds in two steps : 1) it translates CPN to terms of the Multiplicative Intuitionistic Linear Logic (MILL); 2) it proves sequents by constructing proof trees. The translation from CPN to MILL must respect some properties such as the semantic associated to tokens. That is why, the First-Order MILL (MILL1) is used for translation. The reachability between two markings, the initial marking and the final marking, is expressed by a sequent which can be proven (if the initial marking is backward-reachable from the final one) using first-order terms unification and/or marking enhancement.

This paper deals with a new method to study dependability of distributed systems using Colored Petri Nets (CPN) which are a powerful, recognized and intuitive modelling tool. They allow a precise representation of the studied systems. The CPN analysis gives information about static and dynamic behavior of the modelled system and can be used to study questions concerning its dependability. This paper develops a new method of CPN analysis called the Backward reachability. It provides information about different ways of reaching a particular CPN marking that represent, for example, a failure state or a transilient fault. This analysis is performed on an inverse CPN which is obtained by transforming original CPN structure. The illustrative case is the study of a communication protocol composed of three parts: the sender, the receiver ans the network. The Backward reachability analysis done on this system starts by supposing an inconsistent sate in the receiver and looks for the corresponding sender state. The main advantage of this method is that it determines the sequence leading from the initial to the final state independently on the final marking value.

Embedded systems development creates a need of new design, verification and validation technics. Formal methods appear as a very interesting approach for embedded systems analysis, especially for dependability studies. The chosen formalism for this work is based on Colored Petri Net (CPN)for two main reasons : the expressivity and the formal nature. Also, they model easily the static and the dynamic natures of the studied systems. The main challenge of this work is to use existing models, which describe the system structure and/or behavior, to extract the dependability information in a most general case and failure diagnosis information in a particular case. The proposed approach is a CPN structural backward reachability analysis. It can be split in two parts. The first one is to perform the proposed analysis : inverse CPN. It is obtained thanks to structural transformations applied on the original CPN. The second part is the analysis implementation. This part needs some complementary concepts of which the most important is the marking enhancement. The proposed approach is studied under two complementary aspects : algorithmic and theoretic aspects. The first one proposes transformations for the CPN inversion and the analysis implementation. The second aspect (the theoretical one) aims to offer a formal proof for the approach by applying two methods which are linear algebra and linear logic.

RESTful services are an attractive technology for designing and developing web-based applications, as they facilitate reuse, interoperability, and loosely coupled interaction with generic clients (typically web browsers). Building RESTful service composition has received much interest to satisfy complex user requirements. However, verifying the correctness of a composition remains a tedious task. In this paper, we present a formal approach based on Colored Petri Nets (CPNs) to verify RESTful service composition. First, we show how CPNs are utilized for modeling the behavior of resources and their composition. Then, we present how this formal model can be used to verify relevant composition behavior properties. Our solution is illustrated with a scenario built upon an energy management web framework developed within the HIT2GAP H2020 European project 3 .

With the growing use of UML diagrams for software architecture description and the importance of non-functional requirements evaluation at software architecture level, filling the knowledge gap between the architect and the requirements analyst is considered to be significant. In this paper, we propose a new algorithm that enables an architect to transform a software architecture described by use case, sequence and component diagrams into an executable model based on different extensions of Petri Nets. Moreover, we show how to use this Petri net model for simulation, and the implications of this transformation are described completely. Finally, to demonstrate the application of our proposed algorithm, we consider a case study.

Service Oriented Computing(SOC) is becoming a major paradigm for developing next generation of software systems, and one of the major challenges of Service Oriented Computing is testing interactions and collaborations among the distributed and dynamically integrated web services. To support automated test of web service&quot;s collaborations, a formal specification is needed. This thesis proposes a specification of web services collaborations based on Web Services Choreography Description Language (WS-CDL). We identify the basic constructs that can be found in any web services collaboration, and we mapped them to the new WS-CDL based language (WS-CDL+). Finally, A scenario of web services collaboration is developed and specification in WS-CDL+ is provided. This work builds a foundation for automated web services testing in a service oriented computing environment.

The search for improvements in production processes that serve a variant market with flexibility and profitability is a subject widely discussed in diverse sectors of the industry. The approach to this type of problem frequently requires a structured and detailed formal study of production systems using tools such as Coloured Petri Nets (CPN). This tool provides a method to propose and evaluate improvements in the system. Considering the production system as a system that evolves through discrete events, this article presents a procedure with a Top-Down approach to identify, simulate and evaluate the current state of a production system using CPN, this model is used to study improvements in order to analyze the impact on the performance of the production system.

Parametric time Petri nets with inhibitor arcs (PITPNs) support flexibility for timed systems by allowing parameters in firing bounds. In this paper we present and prove correct a concrete and a symbolic rewriting logic semantics for PITPNs. We show how this allows us to use Maude combined with SMT solving to provide sound and complete formal analyses for PITPNs. We develop a new general folding approach for symbolic reachability that terminates whenever the parametric state-class graph of the PITPN is finite. We explain how almost all formal analysis and parameter synthesis supported by the state-of-the-art PITPN tool Roméo can be done in Maude with SMT. In addition, we also support analysis and parameter synthesis from parametric initial markings, as well as full LTL model checking and analysis with user-defined execution strategies. Experiments on three benchmarks show that our methods outperform Roméo in many cases.

Parametric time Petri nets with inhibitor arcs (PITPNs) support flexibility for timed systems by allowing parameters in firing bounds. In this paper we present and prove correct a concrete and a symbolic rewriting logic semantics for PITPNs. We show how this allows us to use Maude combined with SMT solving to provide sound and complete formal analyses for PITPNs. We develop a new general folding approach for symbolic reachability that terminates whenever the parametric state-class graph of the PITPN is finite. We explain how almost all formal analysis and parameter synthesis supported by the state-of-the-art PITPN tool Roméo can be done in Maude with SMT. In addition, we also support analysis and parameter synthesis from parametric initial markings, as well as full LTL model checking and analysis with user-defined execution strategies. Experiments on three benchmarks show that our methods outperform Roméo in many cases.