Workflow Modeling Language Research Articles

Cost analysis for a resource sensitive workflow modelling language

Workflow analysis usually requires domain-specific knowledge from the domain experts, making it a relatively manual process. In addition, workflows often cross organisational boundaries. As a result, minor local modifications in the workflow of a collaborative partner may be propagated to other concurrently running tasks of the workflow, which is difficult for the domain experts to recognise since they only have a limited (local) view of the workflow. Therefore, changes in cross-organisational workflows may result in significant adverse impacts. This paper presents a resource-sensitive formal modelling language, , which has explicit notions of task dependencies, qualitative assessment of resources, time advancement and method execution deadlines. The language allows the workflow analysers to estimate the effect of changes in collaborative workflows with respect to cost in terms of execution time. This paper proposes a static analysis to compute the worst execution time of a cross-organisational workflow modelled in by defining a compositional function that translates an program to a set of cost equations. • In most cases, workflow analysis requires domain-specific knowledge, which makes it a relatively manual process. Additionally, workflows often cross organizational boundaries. Thus, slight local modifications in the workflow of a collaborative partner may be propagated to other concurrently running tasks of the workflow, which is difficult for domain experts to discern since they have only a limited (local) view of the workflow. Therefore, changes in cross-organizational workflows could have adverse effects. This paper presents a resource-sensitive formal modelling language, Rpl. The language has explicit notions for task dependencies, resource allocation and time advancement. The language allows the workflow analyzers to estimate the effect of changes in collaborative workflows with respect to cost in terms of execution time. This paper proposes a static analysis for computing the worst execution time of a cross-organizational workflow modelled in Rpl by defining a compositional function that translates an Rpl program to a set of cost equations.

Representing Business Processes Through a Temporal Data-Centric Workflow Modeling Language: An Application to the Management of Clinical Pathways

Workflow technology has emerged as one of the leading technologies in modeling, redesigning, and executing business processes in several different application domains. Among them, the representation and management of health and clinical processes have been attracting a growing interest. Such processes are in general related to the way each health organization provides the required healthcare services. Health and clinical processes underlie the specification and application of clinical protocols, clinical guidelines, clinical pathways, and the most common clinical/administrative procedures. Current workflow systems are lacking in effective management of three general key aspects that are common (not only) in the clinical/health context: data dependencies, exception handling, and temporal constraints. For example, a laparoscopic intervention may need the results of the concurrent bioptic analysis to be properly concluded while exceptional recovery activities have to be performed in case of emergency evidence during standard treatment; however, the successful application of a fibrinolytic therapy requires a maximum delay of 30 min after the admission into the emergency department. In this paper, we propose TNest, a new advanced, structured, and highly modular workflow modeling language that allows one to easily express data dependencies and time constraints during process design, in addition to exception handling and compensation activities. As for temporal constraints, we focus here on temporal controllability which is the capability of executing a workflow for all possible durations of all tasks satisfying all temporal constraints. Moreover, we analyze the computational complexity of the temporal controllability problem in TNest, and we propose a general algorithm to check the controllability. All the features of TNest that have been considered to model clinical pathways from classical clinical guidelines, i.e., those features for the management of STEMI patients, published by the American College of Cardiology/American Heart Association, will be used throughout the paper as a motivating scenario.

Case-based adaptation of workflows

This paper presents on a Case-based Reasoning approach for automated workflow adaptation by reuse of experience. Agile workflow technology allows structural adaptations of workflow instances at build time or at run time. The approach supports the expert in performing such adaptations by an automated method. The method employs workflow adaptation cases that record adaptation episodes from the past. The recorded changes can be automatically transferred to a new workflow that is in a similar situation of change. First, the notion of workflow adaptation cases is introduced. The sample workflow modeling language CFCN is presented, which has been developed by the University of Trier as a part of the agile workflow management system Cake. Then, the retrieval of adaptation cases is briefly discussed. The case-based adaptation method is explained including the so-called anchor mapping algorithm which identifies the parts of the target workflow where to apply the changes. A formative evaluation in two application domains compares different variants of the anchor mapping algorithm by means of experts assessing the results of the automated adaptation.

Metrics for evaluation of workflow models: An experiment for validation

Due to the dynamism of business, it is very important to support continuous improvement and automation of business processes. The Workflow Management Systems WMS is one of the most significant technologies for such automation. Likewise, the quality of business process models is essential to facilitate understandability and adaptability of models to the constant changes experienced by the processes they represent. Therefore, it is fundamental to have tools to choose from several modeling alternatives, the most appropriate to the business needs. It is also essential to have tools to measure the quality of these models. Therefore, we propose a set of metrics for measuring the quality of workflow models based on their adaptability and understandability. In addition, we introduce the results of the first practical validation of the metrics through a comparative experiment of two Workflow modeling languages: YAWL Vs UML Activity Diagrams 2.0.

Verifying workflow processes: a transformation-based approach

Workflow modeling is a challenging activity and designers are likely to introduce errors, especially in complex industrial processes. Effective process verification is essential at design time because the cost of fixing errors during runtime is substantially higher. However, most user-oriented workflow modeling languages lack formal semantics that hinders such verification. In this paper, we propose a generic approach based on the model transformation to verify workflow processes. The model transformation includes two steps: first, it formalizes the desirable semantics of each modeling element; secondly, it translates a workflow process with clear semantics to an equivalent Petri net. Thus, we can verify the original workflow process using existing Petri net theory and analysis tools. As a comprehensive case study, verifying workflow processes in an industrial modeling language (TiPLM) is presented. Experimental evaluations on verifying real-world business processes validate our approach.

CONFIGURABLE WORKFLOW MODELS

Workflow modeling languages allow for the specification of executable business processes. They, however, typically do not provide any guidance for the adaptation of workflow models, i.e. they do not offer any methods or tools explaining and highlighting which adaptations of the models are feasible and which are not. Therefore, an approach to identify so-called configurable elements of a workflow modeling language and to add configuration opportunities to workflow models is presented in this paper. Configurable elements are the elements of a workflow model that can be modified such that the behavior represented by the model is restricted. More precisely, a configurable element can be either set to enabled, to blocked, or to hidden. To ensure that such configurations lead only to desirable models, our approach allows for imposing so-called requirements on the model's configuration. They have to be fulfilled by any configuration, and limit therefore the freedom of configuration choices. The identification of configurable elements within the workflow modeling language of YAWL and the derivation of the new "configurable YAWL" language provide a concrete example for a rather generic approach. A transformation of configured models into lawful YAWL models demonstrates its applicability.

Agile Workflow Technology and Case-Based Change Reuse for Long-Term Processes

The increasing dynamics of today’s work impacts the business processes. Agile workflow technology is a means for the automation of adaptable processes. However, the modification of workflows is a difficult task that is performed by human experts. This article discusses the novel approach of agile workflow technology for dynamic, long-term scenarios and on change reuse. First, it introduces new concepts for a workflow modeling language and enactment service, which enable an interlocked modeling and execution of workflows by means of a sophisticated suspension mechanism. Second, it provides new process-oriented methods of case-based reasoning in order to support the reuse of change experience. The results from an experimental evaluation in a real-world scenario highlight the usefulness and the practical impact of this work.

Workflow Patterns

Differences in features supported by the various contemporary commercial workflow management systems point to different insights of suitability and different levels of expressive power. The challenge, which we undertake in this paper, is to systematically address workflow requirements, from basic to complex. Many of the more complex requirements identified, recur quite frequently in the analysis phases of workflow projects, however their implementation is uncertain in current products. Requirements for workflow languages are indicated through workflow patterns. In this context, patterns address business requirements in an imperative workflow style expression, but are removed from specific workflow languages. The paper describes a number of workflow patterns addressing what we believe identify comprehensive workflow functionality. These patterns provide the basis for an in-depth comparison of a number of commercially available workflow management systems. As such, this paper can be seen as the academic response to evaluations made by prestigious consulting companies. Typically, these evaluations hardly consider the workflow modeling language and routing capabilities, and focus more on the purely technical and commercial aspects.

PROCLETS: A FRAMEWORK FOR LIGHTWEIGHT INTERACTING WORKFLOW PROCESSES

The focus of traditional workflow management systems is on control flow within one process definition. The process definition describes how a single case (i.e. workflow instance) in isolation is handled. For many applications this paradigm is inadequate. Interaction between cases to support communication and collaboration is at least as important. This paper introduces and advocates the use of interacting proclets, i.e. lightweight workflow processes. By promoting interactions to first-class citizens it is possible to model complex workflows in a more natural manner. In addition, the expressive power and flexibility are improved compared to the more traditional workflow modeling languages.

Analyzing process models using graph reduction techniques

The foundation of a process model lies in its structural specifications. Using a generic process modeling language for workflows, we show how a structural specification may contain deadlock and lack of synchronization conflicts that could compromise the correct execution of workflows. In general, identification of such conflicts is a computationally complex problem and requires development of effective algorithms specific for the target modeling language. We present a visual verification approach and algorithm that employs a set of graph reduction rules to identify structural conflicts in process models for the given workflow modeling language. We also provide insights into the correctness and complexity of the reduction process. Finally, we show how the reduction algorithm may be used to count possible instance subgraphs of a correct process model. The main contribution of the paper is a new technique for satisfying well-defined correctness criteria in process models.