Synchronic Distance Based Workflow Logic Specification

The definition and simulation of processes using Work flow technology is becoming more and more popular. In that way, to standardize and simulate complex processes it is needed high expressive languages able to be automatically executed by computers. Currently, high expressive languages that can be used for simulation and definition of processes are based in Petri Nets technology. Nevertheless, Petri Nets are difficult to understand by processes experts with no computer science training or expertise and are more complex to be executed than other simpler approaches like finite automatons. In this paper an automata based mathematical tool with a high expressivity capacity is presented. This framework is easier to understand also by non computer science expert sand its automation is simple in order to allow to experts to define formal work flows that can be easily automated.

To support and drive a business process with a software system means influencing the way process participants conduct their daily work. An analysis of the relationships between organizational processes, support systems, and process participants calls for a continuous alignment and parallel evolution of the intended business process and the supporting software system. Here, the primary information needed is how process participants work with the new system and where and why they deviate from the intended process. Delta analysis with workflow logs employs workflow logs recorded during system use to compare process enactment with its prescription: log entries are related with instances of business process activities of an explicit process definition, and the timely ordering of these entries is compared with the ordering of the activities implied by the process model. If the orderings comply, the log fits the model. Log entries and activities can be on arbitrary levels of abstraction and arbitrary granularity. The results of such an analysis can be utilized as an unbiased data basis for further discussions. Moreover, compared with traditional approaches such as interviews and observations, time and costs can be saved. The paper presents the concept, a feasibility study, some aspects of the related theoretical challenges, a prototypical implementation, and initial case study results.

A continuous evolution of business process parameters, constraints and needs, hardly foreseeable initially, requires from the business process management systems a continuous design and a reliable process model. In this paper, we are interested in developing a reactive design through a process log analysis ensuring process re-engineering and execution reliability. We propose to analyse workflow logs to discover workflow transactional behavior and to improve and correct related recovery mechanisms subsequently. Our approach starts by collecting workflow logs. Then, we build, by statistical analysis techniques, an intermediate representation specifying elementary dependencies between activities. These dependencies are refined to mine the transactional workflow model. The analysis of the discrepancies between the discovered model and the initially designed model enables us to detect design gaps, concerning particularly the recovery mechanisms. Thus, based on this mining step, we apply a set of rules on the initially designed workflow to improve workflow reliability.

This chapter introduces a theoretical frame for the Process Definition (PD) validation in Workflow or in those processes with temporal restrictions. The Interface 1 of Workflow makes the PD of the Work Flow Reference Model. This interface combined with Petri Nets with Clocks (PNwC) allows the formalization and verification of systems, based on the Petri Net theory and the extension. This extension allows the specification of temporal requirements via clocks specification, using temporal invariants for the places and temporal conditions in the transitions.

During the early 1990s, workflow technologies were the only ones to offer a transversal integration capacity to the enterprise applications, thus allowing the representation and the enactment of business processes. However, the formalisms developed for workflow specifications were almost systematically activity oriented. Consequently, the resulting process definitions have the advantage to be easily transformable in executable code, but the disadvantage of being prescriptive and rigid. Recent works underline the needs in term of flexible and adaptive workflows, whose execution can evolve according to situations that cannot always be prescribed. In fact, a flexible representation of business processes is an asset to maintain the fit between business processes and their supporting systems in an evolving environment. This article proposes a conceptual framework for an intention‐driven modeling of flexible workflow applications. The purpose of the underlying modeling formalism is to define an integration/orchestration for islands of business process chunks and their support systems in order to create and to maintain the fit between them. The modeling framework offers the ability to represent in the same business process definition the well‐structured process chunks as well as the ill‐structured orad hocones. Copyright © 2005 John Wiley & Sons, Ltd.

Because of the complexity of metabolic networks and their regulation, formal modelling is a useful method to improve the understanding of these systems. An essential step in network modelling is to validate the network model. Petri net theory provides algorithms and methods, which can be applied directly to metabolic network modelling and analysis in order to validate the model. The metabolism between sucrose and starch in the potato tuber is of great research interest. Even if the metabolism is one of the best studied in sink organs, it is not yet fully understood. We provide an approach for model validation of metabolic networks using Petri net theory, which we demonstrate for the sucrose breakdown pathway in the potato tuber. We start with hierarchical modelling of the metabolic network as a Petri net and continue with the analysis of qualitative properties of the network. The results characterize the net structure and give insights into the complex net behaviour.

Many requirements for a business process depend on the workflow execution data that includes common data for all the population of processes, state of resources, state of processes, etc. The natural way to specify and implement such requirements is to put them into the process definition. In order to do it, we need: (1) a generalised workflow metamodel that includes data on the workflow environment, process definitions, and process execution; (2) a powerful and flexible query language addressing the metamodel; (3) integration of a query language with a business process definition language. In this paper the mentioned workflow metamodel together with the business process query language BPQL is presented. BPQL is integrated with the XML Process Definition Language (XPDL) increasing significantly its expressiveness and flexibility. We also present practical results for application of the proposed language in the OfficeObjects® WorkFlow system.

We investigate the kanban assignment problem for assembly kanban systems. We use REMO, a general purpose tool for optimization. REMO includes several algorithms like hill climbing and genetic algorithms and has an easily adaptable interface to performance analysis tools. As we try to find an optimal kanban assignment with respect to certain performance measures of the system, a fast performance analysis is a crucial factor for sensible and successful application of optimization algorithms. For this purpose we introduce Petri nets including queueing nets (PNiQ) as modeling formalism especially suited for optimization of arbitrary kanban systems. At modeling level, PNiQ allow the use of both the concise description of queueing nets where possible and the notation of stochastic Petri nets where needed, e.g. to model fork/join needed for the matching of kanbans and parts. Approximate performance analysis is carried out by decomposition and aggregation of the queueing net parts. This technique provides a fast numerical solution even for large systems as important requirement for the application of optimization algorithms. The optimization not only yields optimal kanban assignments for various kanban systems but also a common pattern in the set of solutions can be recognized.

The theoretical basis and implementation solution of business process simulation and analysis system (BPSAS) is put forward in this paper. With workflow technology, Petri net theory and simulation technology, the workflow engine independent business process analyzing system is realized to provide Petri net based business process analysis. Further more, an example is illustrated to demonstrate how to analyze business process in order to select optimized model. And at the same time, as a business process analyzing tool, it supports the specified BPM (business process management) process.

The automatic detection of divergences from a desired process behavior is a common research topic in the business process management community. An established technique to analyze processes is called conformance checking. Given a definition of a process in form of a process model, conformance checking can be used to test whether the executions of a process contained in a so-called event log data structure are conforming with the process as it was defined. The result is a comparison of the execution traces and their respective correct execution, according to the process model. This technique provides insights into where the divergence has occurred and how the execution must be altered to conform to the process model. However, a problem is that it requires a process model to be available. Process models in the correct format are not always available. Contrary to conformance checking, process anomaly detection aims to find anomalous executions without relying on a predefined process model. A process anomaly detection algorithm derives the process logic from the event log itself and exploits the patterns found within the event log to distinguish normal from anomalous process executions. Though process anomaly detection provides the benefit of not relying on a process model, it typically does not provide the level of detail that conformance checking does. A process execution can either be normal or it can be anomalous. This dissertation proposes process anomaly correction, a novel approach that combines the benefits of conformance checking and process anomaly detection. Given only an event log, process anomaly correction detects anomalous executions, clearly indicates where the anomaly has occurred during the execution and suggests possible corrective measures. The solution presented in this work is based on a new concept to the field of process anomaly detection: Process learning. In process learning, the task of understanding the process based on the example data is transformed into a learning problem in which a neural network is trained to predict the very next activity in a running process execution. The resulting machine learning model thus represents an approximation of the real process that created the data. This cumulative dissertation consists of five contributions to the field of business process management that demonstrate how, starting from a process anomaly detection, process anomaly correction is achieved in a series of four steps. (1) Process learning is employed to generate an approximated model of the process logic. (2) The limitation of only distinguishing between normal and anomalous process executions is overcome by employing the process learning model which processes the process executions on a finer level of detail than existing approaches. (3) The necessity of providing manual threshold settings, as it is typical for process anomaly detection algorithms, is replaced by an automatic parameterization utilizing the process learning model. (4) The predictive capabilities of the process learning model are exploited to generate possible corrections of detected anomalies. The resulting process anomaly correction approach can be employed in scenarios where classic conformance checking would be infeasible, due to the restriction of relying on a process model. Furthermore, it can be employed alongside classical conformance checking, for it incorporates more information coming from the event log than classical conformance checking (such as employees executing a process step, in which country the process is executed, etc.), and thus provides a new perspective for the process analyst.

The PETRI NETS 2023 proceedings deal with the application and theory of petri nets, distributed and concurrency systems, etc.

A general stochastic hybrid process (GSHP) is a mathematical formalism that covers most of the requirements posed by the modelling of complex operations, such as time dependencies, multi-dimensional continuous as well as discrete processes, discontinuities, randomness and model uncertainties. In addition, it is possible to study GSHP by using stochastic analysis methodologies, thereby empowering it with powerful mathematical properties. This guarantees unambiguous simulation possibility of the model and allows speeding up this simulation while keeping the model properties intact. However, using GSHP to construct a model of a complex operation is not easy. To support the modelling and the subsequent verification both by mathematical and by multiple operational domain experts, a supporting graphical modelling formalism is desired. Petri nets have shown to be useful for developing models of various complex applications. Typical Petri net features are concurrency and synchronisation mechanism, hierarchical and modular construction, and natural expression of causal dependencies, in combination with graphical and analytical representations. The aim of this thesis is to combine the strengths of Petri net modelling formalisms and those of GSHP. First, dynamically coloured Petri nets (DCPN) are developed, and proof of equivalence is provided with piecewise deterministic Markov processes, which is a particular class of GSHP. Next, DCPN are extended to stochastically and dynamically coloured Petri nets (SDCPN), and proof of equivalence is provided with GSHP. Subsequently, SDCPN are extended to SDCPN with interconnection mapping types (SDCPNimt) and proof of equivalence is provided with both SDCPN and GSHP. It is shown with illustrative air transport examples that these three classes of Petri net are very effective when it comes to the compositional modelling of operations consisting of many distributed components that behave and interact in a dynamic way with many uncertainties. With the equivalence relations between these formalisms, the properties and strengths of the various approaches are combined. The many applications of the approach developed in this thesis, executed at NLR and beyond, show that both the approach and its combined strengths are acknowledged and supported by practice.

Based on the workflow management coalition (WFMC) standard and component software technologies, this paper addresses our Petri-nets-based approach for workflow and process automation. Petri nets provide graphical and mathematical formalisms for work-flow process definition and analysis. In this paper, we will present how to use Petri nets and a toolkit NCUPN (National Central University Petri Nets toolkit) for process definition and analysis. NCUPN is a Petri nets modeling and analysis toolkit developed to help software engineers in drawing and doing analysis. Once a workflow process is drawn using NCUPN, analysis can be done automatically. In this paper, we will demonstrate how to use NCUPN to analyze behavioral properties of workflow process, such as deadlock, liveness, safety, and starvation.

Current workflow products can support more complex modeling of business processes, workflow engine mechanism is well researched, but the link between organizational elements and process activities is less well understood. In access control, most products can only support fixed role-based task assignment, not enough in considering more complex security policies, such as DSOD, task binding of duties, and temporal constraints, that important in dynamic workflow system. This paper examines workflow access control requirement in practice, analyzes WFMC workflow meta-model, and adopts the R&TBAC approach to separate role-based organization and task-based authorization-step modeling, and especially designs an agent-based dynamic policy enforcement mechanism to bridge the gap. The intelligent task assigning agent to be defined as a virtual participant in workflow process definition, and creating within workflow engine controlled available task instance, acts as to evaluate task dynamic authorization policy to provide eligible task participant role-set based on its information model. This paper gives a formal specification of the workflow authorization model, and designs the agent information model, assigning policy model, and function model in detail. The modeling approach can widely adapt to various existing workflow systems and can automatically change policy as enterprise organization or business process definition need changing.

Many theorists would agree that, had it not been for Petri Nets, the development of the Workflow Engine might never have occurred. Given the current status of highly-available theory, system administrators shockingly desire implementation of workflow engine based on petri nets, which embodies the unfortunate principles of permutable theory. Here, we concentrate our efforts on proving that the well-known large-scale algorithm for the workflow engine based on petri nets.