Andreas Wombacher

On Measuring Process Model Similarity Based on High-Level Change Operations

For various applications there is the need to compare the similarity between two process models. For example, given the as-is and to-be models of a particular business process, we would like to know how much they differ from each other and how we can efficiently transform the as-is to the to-be model; or given a running process instance and its original process schema, we might be interested in the deviations between them (e.g. due to ad-hoc changes at instance level). Respective considerations can be useful, for example, to minimize the efforts for propagating the schema changes to other process instances as well. All these scenarios require a method to measure the similarity or distance between two process models based on the efforts for transforming the one into the other. In this paper, we provide an approach using digital logic to evaluate the distance and similarity between two process models based on high-level change operations (e.g. to add, delete or move activities). In this way, we can not only guarantee that model transformation results in a sound process model, but also ensure that related efforts are minimized.

Matchmaking for business processes based on choreographies

Web services have a potential to enhance B2B e-commerce over the Internet by allowing companies and organizations to publish their business processes on service directories where potential trading partners can find them. This can give rise to new business paradigms based on ad-hoc trading relations as companies, particularly small to medium scale, can cheaply and flexibly enter into fruitful contracts, e.g., through subcontracting from big companies by simply publishing their business processes and the services they offer. More business process support by the Web service infrastructure is however needed before such a paradigm change can materialize. A service for searching and matchmaking of business processes does not yet exist in the current infrastructure. We believe that such a service is needed and will enable companies and organizations to be able to establish ad-hoc business relations without relying on manually negotiated interorganizational workflows. We give a formal semantics to business process matchmaking based on finite state automata extended by logical expressions associated to states.

Transforming BPEL into annotated deterministic finite state automata for service discovery

Web services advocate loosely coupled systems, although current loosely coupled applications are limited to stateless services. The reason for this limitation is the lack of a method supporting matchmaking of state dependent services exemplarily specified in BPEL. In particular, the senders requirement that the receiver must support all possible messages sent at a certain state are not captured by models currently used for service discovery. Annotated deterministic finite state automata provide this expressiveness. In this paper the transformation of a local process specification given in BPEL to annotated deterministic finite state automata is presented.

Evolution of process choreographies in DYCHOR

Process-aware information systems have to be frequently adapted due to business process changes One important challenge not adequately addressed so far concerns the evolution of process choreographies, i.e., the change of interactions between partner processes in a cross-organizational setting If respective modifications are applied in an uncontrolled manner, inconsistencies or errors might occur in the sequel In particular, modifications of private processes performed by a single party may affect the implementation of the private processes of partners as well In this paper we present the DYCHOR (DYnamic CHOReographies) framework which allows process engineers to detect how changes of private processes may affect related public views and – if so – how they can be propagated to the public and private processes of partners In particular, DYCHOR exploits the semantics of the applied changes in order to automatically determine the adaptations necessary for the partner processes Altogether our framework provides an important contribution towards the realization of adaptive, cross-organizational processes.

THE MINADEPT CLUSTERING APPROACH FOR DISCOVERING REFERENCE PROCESS MODELS OUT OF PROCESS VARIANTS

During the last years a new generation of adaptive Process-Aware Information Systems (PAIS) has emerged, which enables dynamic process changes at runtime, while preserving PAIS robustness and consistency. Such adaptive PAIS allow authorized users to add new process activities, to delete existing activities, or to change pre-defined activity sequences during runtime. Both this runtime flexibility and process configurations at build-time, lead to a large number of process variants being derived from the same process model, but slightly differing in structure due to the applied changes. Generally, process variants are expensive to configure and difficult to maintain. This paper presents selected results from our MinAdept project. In particular, we provide a clustering algorithm that fosters learning from past process changes by mining a collection of process variants. As mining result we obtain a process model for which average distance to the process variant models becomes minimal. By adopting this process model as reference model in the PAIS, need for future process configuration and adaptation decreases. We have validated our clustering algorithm by means of a case study as well as comprehensive simulations. Altogether, our vision is to enable full process lifecycle support in adaptive PAIS.

Discovering Reference Process Models by Mining Process Variants

Recently, a new generation of adaptive Process-Aware Information Systems (PAIS) has emerged, which allows for dynamic process and service changes (e.g., to insert, delete, and move activities and service executions in a running process). This, in turn, has led to a large number of process variants derived from the same model, but differing in structure due to the applied changes. Generally, such process variants are expensive to configure and difficult to maintain. This paper provides a sophisticated approach which fosters learning from past process changes and allows for mining process variants. As a result we obtain a generic process model for which the average distance between this model and the respective process variants becomes minimal. By adopting this generic model in the PAIS, need for future process configuration and adaptation decreases. We have validated the proposed mining method and implemented it in a powerful proof-of-concept prototype.

Monitoring Dependencies for SLAs: The MoDe4SLA Approach

In service oriented computing different techniques for monitoring service level agreements (SLAs) are available. Many of these monitoring approaches focus on bilateral agreements between partners. However, when monitoring composite services it is not only important to figure out whether SLAs are violated, but we also need to analyze why these violations have occurred. When offering a composite service a company depends on its content providers to meet the service level they agreed upon. Due to these dependencies a company should not only monitor the SLA of the composite service, but also the SLAs of the services it depends on. By analyzing and monitoring the composite service in this way, causes for SLA violations can be easier found. In this paper we demonstrate how to analyze SLAs during development phase and how to monitor these dependencies using event logs during runtime. We call our approach MoDe4SLA (monitoring dependencies for SLAs).

Matchmaking for Business Processes Based on Choreographics

Web services have a potential to enhance B2B e-commerce over the Internet by allowing companies and organizations to publish their business processes on service directories where potential trading partners can find them. This can give rise to new business paradigms based on ad-hoc trading relations as companies, particularly small to medium scale, can cheaply and flexibly enter into fruitful contracts, for example through subcontracting from big companies by simply publishing their business processes and the services they offer. More business process support by the Web service infrastructure is however needed before such a paradigm change can materialize. A service for searching and matchmaking of business processes does not yet exist in the current infrastructure. We believe that such a service is needed and will enable companies and organizations to be able to establish ad-hoc business relations without relying on manually negotiated interorganizational workflows. This article gives a formal semantics to business process matchmaking based on finite state automata extended by logical expressions associated to states.

Evaluation of technical measures for workflow similarity based on a pilot study

Service discovery of state dependent services has to take workflow aspects into account To increase the usability of a service discovery, the result list of services should be ordered with regard to the relevance of the services Means of ordering a list of workflows due to their similarity with regard to a query are missing In this paper different similarity measures are presented and evaluated based on a pilot of an empirical study In particular the different measures are compared with the study results It turns out that the quality of the different measures differ significantly.

Indexing Business Processes based on Annotated Finite State Automata

The existing service discovery infrastructure with UDDI as the de facto standard, is limited in that it does not support more complex searching based on matching business processes. Two business processes match if they agree on their simple services, their processing order as well as any mandatory or optional requirements for the service. This matching semantics can be formalized by modelling business processes as annotated finite state automata (aFSAs) and deciding emptiness of the intersection aFSA. Computing the intersection of aFSAs and deciding emptiness are computationally expensive, being more than quadratic on the number of states and transitions, thus does not scale for large service repositories. This paper presents an approach for indexing and matching business processes modeled as aFSAs, for the purpose of service discovery. Evaluation of this approach shows a performance gain of several orders of magnitude over sequential matching and a linear complexity with regard to the data set size