Showing papers on "Process architecture published in 2006"

An Architecture for Provenance Systems

Abstract: This document covers the logical and process architectures of provenance systems. The logical architecture identifies key roles and their interactions, whereas the process architecture discusses distribution and security. A fundamental aspect of our presentation is its technology-independent nature, which makes it reusable: the principles that are exposed in this document may be applied to different technologies.

Supervisory Control of Concurrent Systems: A Petri Net Structural Approach

Abstract: Preface.- Symbols.- Introduction.- An Introduction to Petri Nets.- The Supervision of Petri Nets.- Enforcing General Specifications.- Decentralized Supervision of Petri Nets.-Deadlock and Liveness Properties of Petri Nets.- Liveness Enforcement in Petri Nets: A Structural Approach. Part I.- Liveness Enforcement in Petri Nets: A Structural Approach. Part II.- DES Control of Concurrent Hybrid Systems.- Hybrid System Level Control.-References.- Index

Time Petri Nets Analysis with TINA

Abstract: Beside the usual graphic editing and simulation facilities, the software tool Tina may build a number of state space abstractions for Petri nets or Time Petri nets, preserving certain classes of properties. For Petri nets, these abstractions help preventing combinatorial explosion and rely on so-called partial order techniques such as covering steps and/or persistent sets. For Time Petri nets, that have in general infinite state spaces, they provide finite representation of their behavior, in terms of state class graphs.

A Rule-Based Approach for Process Discovery: Dealing with Noise and Imbalance in Process Logs

Abstract: Effective information systems require the existence of explicit process models. A completely specified process design needs to be developed in order to enact a given business process. This development is time consuming and often subjective and incomplete. We propose a method that constructs the process model from process log data, by determining the relations between process tasks. To predict these relations, we employ machine learning technique to induce rule sets. These rule sets are induced from simulated process log data generated by varying process characteristics such as noise and log size. Tests reveal that the induced rule sets have a high predictive accuracy on new data. The effects of noise and imbalance of execution priorities during the discovery of the relations between process tasks are also discussed. Knowing the causal, exclusive, and parallel relations, a process model expressed in the Petri net formalism can be built. We illustrate our approach with real world data in a case study.

Petri nets and other models of concurrency - ICATPN 2006 : 27th International Conference on Applications and Theory of Petri Nets and Other Models of Concurrency, Turku, Finland, June 26-30, 2006 ; proceedings

Abstract: Invited Papers.- Invariant Based Programming.- On the Integration of UML and Petri Nets in Software Development.- Component Tools: Integrating Petri Nets with Other Formal Methods.- Using Colored Petri Nets and Tools to Support Mobile Terminal and Network Software Development.- Full Papers.- Compensation in Workflow Nets.- The Synthesis Problem of Netcharts.- Non-sequential Behaviour of Dynamic Nets.- Complete Finite Prefixes of Symbolic Unfoldings of Safe Time Petri Nets.- On the Computation of Stubborn Sets of Colored Petri Nets.- On the Construction of Pullbacks for Safe Petri Nets.- From Petri Nets to Differential Equations - An Integrative Approach for Biochemical Network Analysis.- How Expressive Are Petri Net Schemata?.- A New Approach to the Evaluation of Non Markovian Stochastic Petri Nets.- Nested Nets for Adaptive Systems.- Analyzing Software Performance and Energy Consumption of Embedded Systems by Probabilistic Modeling: An Approach Based on Coloured Petri Nets.- Infinite Process Semantics of Inhibitor Nets.- Towards Synthesis of Petri Nets from Scenarios.- Designing Reversibility-Enforcing Supervisors of Polynomial Complexity for Bounded Petri Nets Through the Theory of Regions.- On the Step Explosion Problem.- Prospective Analysis of Cooperative Provision of Industrial Services Using Coloured Petri Nets.- Tool Papers.- Can I Execute My Scenario in Your Net? VipTool Tells You!.- Exhost-PIPE: PIPE Extended for Two Classes of Monitoring Petri Nets.- ArgoSPE: Model-Based Software Performance Engineering.- Petriweb: A Repository for Petri Nets.- Geist3D, a Simulation Tool for Geometry-Driven Petri Nets.- The BRITNeY Suite Animation Tool.

Analyzing Compatibility of BPEL Processes

Abstract: The Business Process Execution Language for Web Services provides a powerful technology to aggregate encapsulated functionalities and define high-value Web services - backed by various development and runtime environments of major software companies. Nevertheless, modeling and composing BPEL processes is still a complicated, time and money consuming, and errorprone activity. Formal methods like Petri nets enable the effective analysis of one single BPEL process as well as the comparison of multiple given BPEL models, and the generation of a BPEL model out of another. The current paper presents an prototypically implemented analysis framework that integrates those methods into IBM’s business integration tools. The value of such a framework is illustrated by analyzing behavioral compatibility between BPEL processes, one of the most crucial properties in real-world B2B scenarios.

Performance analysis using CPN tools

Abstract: This paper provides an overview of new facilities for performance analysis using Coloured Petri Nets and the tool CPN Tools. Coloured Petri Nets is a formal modeling language that is well suited for modeling and analyzing large and complex systems. The new facilities include support for collecting data during simulations, for generating different kinds of performance-related output, and for running multiple simulation replications. A simple example of a network protocol is used to illustrate the flexibility of the new facilities.

Complete finite prefixes of symbolic unfoldings of safe time petri nets

Abstract: Time Petri nets have proved their interest in modeling real-time concurrent systems. Their usual semantics is defined in term of firing sequences, which can be coded in a (symbolic and global) state graph, computable from a bounded net. An alternative is to consider a “partial order” semantics given in term of processes, which keep explicit the notions of causality and concurrency without computing arbitrary interleavings. In ordinary place/transition bounded nets, it has been shown for many years that the whole set of processes can be finitely represented by a prefix of what is called the “unfolding”. This paper defines such a prefix for safe time Petri nets. It is based on a symbolic unfolding of the net, using a notion of “partial state”.

From logical regulatory graphs to standard petri nets: dynamical roles and functionality of feedback circuits

Abstract: Logical modelling and Petri nets constitute two complementary approaches for the dynamical modelling of biological regulatory networks. Leaning on a translation of logical models into standard Petri nets, we propose a formalisation of the notion of circuit functionality in the Petri net framework. This approach is illustrated with the modelling and analysis of a molecular regulatory network involved in the control of Th-lymphocyte differentiation.

Nested nets for adaptive systems

Abstract: We consider nested nets, i.e. Petri nets in which tokens can be Petri nets themselves. We study the value semantics of nested nets rather than the reference semantics, and apply nested nets to model adaptive workflow, i.e. flexible workflow that can be modified during the execution. A typical domain with a great need for this kind of workflow is health care, from which domain we choose the running example. To achieve the desired flexibility we allow transitions that create new nets out of the existing ones. Therefore, nets with completely new structure can be created at the run time. We show that by careful selection of basic operations on the nets we can obtain a powerful modeling formalism that enforces correctness of models. Moreover, the formalism can be implemented based on existing workflow engines.

Petri net ontology

Abstract: The paper presents the Petri net ontology that enables sharing Petri nets on the Semantic Web. Previous work on formal methods for representing Petri nets mainly defines tool-specific descriptions or formats for model interchange. However, such efforts do not provide a suitable description for using Petri nets on the Semantic Web. This paper uses the Petri net UML model as a starting point for implementing the ontology. Resulting Petri net models are represented on the Semantic Web using XML-based ontology languages, RDF and OWL. We implemented a Petri net tool, P3, which can be used as a knowledge acquisition tool based on the Petri net ontology.

Yasper: a tool for workflow modeling and analysis

Abstract: This paper presents Yasper, a tool for modeling, analyzing and simulating workflow systems, based on Petri nets. Yasper puts Petri net modeling in the hands of business analysts and software architecture designers. They can specify systems in familiar terms (XOR choice, workflow, cases, roles, processing time and cost), and can directly run manual and automatic simulations on the resulting models to analyze correctness and performance. Yasper was designed to cooperate with other tools, such as Petri net analyzers, and off-the-shelf software for data (color) handling and forms handling.

Resource-Constrained Workflow Nets

Abstract: We study concurrent processes modelled as workflow Petri nets extended with resource constrains. Resources are durable units that can be neither created nor destroyed: they are claimed during the handling procedure and then released again. Typical kinds of resources are manpower, machinery, computer memory. We define structural criteria based on traps and siphons for the correctness of workflow nets with resource constraints. We also extend the soundness notion for workflow nets to the workflow nets with resource constraints; extra conditions concern the durability of resources. We prove some properties of sound resource-constrained workflow nets.

Petri Nets for Game Plot

Abstract: We have developed a technique for authoring a nonlinear plot and for managing a story according to the plot in an interactive story-based virtual reality application The technique exploits Petri Nets that alter reactive plans controlling individual actors Its main advantage is that it allows for iterative design and copes with large virtual worlds inhabited with tens of actors In this paper, we describe the technique and a prototype application

Process semantics for membrane systems

Abstract: A process model based on Petri nets is proposed to describe the structure of the behaviour of basic membrane systems. In [12], a systematic and structural link has been established between a basic class of membrane systems and Petri nets. To capture the compartmentisation of membrane systems, Place/Transition nets with explicit localities have been introduced. Each locality identifies a distinct set of transitions which may only be executed synchronously, i.e., in a locally maximal concurrent manner. Here, we develop the notion of a process for these nets. The resulting formalism should be of use in the investigation of the ways in which computations of membrane systems can evolve.

State space computation and analysis of Time Petri Nets

Abstract: The theory of Petri Nets provides a general framework to specify the behaviors of real-time reactive systems and Time Petri Nets were introduced to take also temporal specifications into account. We present in this paper a forward zone-based algorithm to compute the state space of a bounded Time Petri Net: the method is different and more efficient than the classical State Class Graph. We prove the algorithm to be exact with respect to the reachability problem. Furthermore, we propose a translation of the computed state space into a Timed Automaton, proved to be timed bisimilar to the original Time Petri Net. As the method produce a single Timed Automaton, syntactical clocks reduction methods (DAWS and YOVINE for instance) may be applied to produce an automaton with fewer clocks. Then, our method allows to model-check T-TPN by the use of efficient Timed Automata tools.

Modeling and execution of complex attack scenarios using interval timed colored Petri nets

Abstract: The commonly used flaw hypothesis model (FHM) for performing penetration tests provides only limited, high level guidance for the derivation of actual penetration attempts. In this paper, a mechanism for the systematic modeling, simulation, and exploitation of complex multistage and multiagent vulnerabilities in networked and distributed systems based on stochastic and interval-timed colored Petri nets is described and analyzed through case studies elucidating several properties of Petri net variants and their suitability to modeling this type of attack.

Stochastic petri nets modeling using spn

Abstract: This paper introduces SPN@, a tool for the graphical modeling of intricate dynamics scenarios relevant to safety, reliability, and availability. Implemented in SPN@ is a novel concept of aging tokens, enhancing colored stochastic Petri net formalism, and providing a visual and practical means for assessing complex dynamic scenarios. The examples provided serve to indicate a wide range of practical applications of SPN@, including a classical problem of shared load, repairable system with parallel tasks, and modeling of a system that undergoes both preventive and corrective maintenance with the associated consideration of risk trade offs

Designing reversibility-enforcing supervisors of polynomial complexity for bounded petri nets through the theory of regions

Abstract: This paper proposes an analytical method for the synthesis of reversibility-enforcing supervisors for bounded Petri nets The proposed me-thod builds upon recent developments from (i) the theory of regions, that enables the design of Petri nets with pre-specified behavioral requirements, and (ii) the theory concerning the imposition of generalized mutual exclusion constraints on the net behavior through monitor places The derived methodology takes the form of a Mixed Integer Programming formulation, which is readily solvable through canned optimization software The last part of the paper discusses extensions of the presented method so that it accommodates uncontrollable behavior and any potential complications arising from the large-scale nature of the underlying plant nets and their behavioral spaces Finally, the relevance and the efficacy of the proposed approach is demonstrated through its application in the synthesis of liveness-enforcing supervisors for process-resource nets

On performance monotonicity and basic servers semantics of continuous Petri nets

Abstract: Continuous Petri nets were introduced as an approximation to deal with the state explosion problem which can appear in discrete event models. When time is introduced, the flow through a fluidified transition can be defined in many ways. The most used in literature are infinite and finite servers semantics. Both can be seen as derived from stochastic Petri nets. The practical problems addressed in this contribution are: (1) a sufficient condition for the performance monotonicity, and (2) a study of the transition semantics, always related to continuous Petri nets. We prove that under some conditions, the subclass of mono-T-semiflow is monotone and also for the same class of nets we prove a property for which infinite servers semantics offers a better approximation than finite servers semantics for the discrete model

Synchrony and asynchrony in membrane systems

Abstract: We consider synchrony and asynchrony in the behavior of various models of membrane systems, which may differ in the way individual reactions are defined as well as in the way multisets of these reactions can be executed in a single computational step. We concentrate on the properties of ongoing computations, including the unbounded ones. Our focus is on the properties of system states involved in such computations as well as on concurrency and causality relationships between executed reactions. This should be contrasted with the approach which investigates different notions of ‘results' produced through halting computations of membrane systems. As a formal behavioral model we use Petri nets and their processes which are very well suited to capture the notion of an execution in a concurrent context. We continue our earlier work reported in [15], where a systematic and structural link has been established between a basic class of membrane systems and Petri nets. Here, we look at some natural extensions of this basic class of membrane systems and investigate the ways in which they can be represented within the behavioral model provided by Petri nets.

Choreography Conformance Checking: An Approach based on BPEL and Petri Nets

Abstract: Recently, languages such as BPEL and WS-CDL have been proposed to describe interactions between services and their behavioral dependencies. The emergence of these languages heralds an era where richer service descriptions, going beyond WSDL-like interfaces, will be available. However, what can these richer service descriptions serve for? This talk discussed the use of event logs of web services and behavioral service descriptions as input for process mining and conformance checking. Conformance checking is the act of verifying whether or not one or more parties stick to an agreed-upon behavior, by observing their actual behavior as recorded in message logs. This talk shows that it is possible to translate BPEL business abstract processes to Petri nets and to relate SOAP messages to transitions in the Petri net. The approach has been implemented in the ProM framework.

Advances in Verification of Time Petri Nets and Timed Automata: A Temporal Logic Approach (Studies in Computational Intelligence)

Abstract: Specifying Timed Systems and Their Properties.- Petri Nets with Time.- Timed Automata.- From Time Petri Nets to Timed Automata.- Main Formalisms for Expressing Temporal Properties.- Model Generation and Verification.- Abstract Models.- Explicit Verification.- Verification Based on Satisfiability Checking.