Gero Decker

Efficient Compliance Checking Using BPMN-Q and Temporal Logic

Compliance rules describe regulations, policies and quality constraints business processes must adhere to. Given the large number of rules and their frequency of change, manual compliance checking can become a time-consuming task. Automated compliance checking of process activities and their ordering is an alternative whenever business processes and compliance rules are described in a formal way. This paper introduces an approach for automated compliance checking. Compliance rules are translated into temporal logic formulae that serve as input to model checkers which in turn verify whether a process model satisfies the requested compliance rule. To address the problem of state-space explosion we employ a set of reduction rules. The approach is prototypically realized and evaluated.

BPEL4Chor: Extending BPEL for Modeling Choreographies

The business process execution language (BPEL) is a language to orchestrate web services into a single business process. In a choreography view, several processes are interconnected and their interaction behavior is described from a global perspective. This paper shows how BPEL can be extended for defining choreographies. The proposed extensions (BPEL4Chor) distinguish between three aspects: (i) participant behavior descriptions, i.e. control flow dependencies in each participant, (ii) the participant topology, i.e. the existing participants and their interconnection using message links and (iii) participant groundings, i.e. concrete configurations for data formats and port types. As BPEL itself is used unchanged, the extensions facilitate a seamless integration between service choreographies and orchestrations. The suitability of the extensions is validated by assessing their support for the Service Interaction Patterns.

Oryx --- An Open Modeling Platform for the BPM Community

In the academic business process management community, tooling plays an increasingly important role [8,6]. There are good reasons for this fact. Firstly, theoretical concepts benefit from exploration using prototypical implementation of the concepts. By experimentation based on real-world business processes, concepts can be evaluated and refined. Secondly, the practical applicability of the research work can be demonstrated, which is important to raise awareness of academic BPM research to practitioners.

Interacting services: From specification to execution

Interacting services play a key role to realize business process integration among different business partners by means of electronic message exchange. In order to provide seamless integration of these services, the messages exchanged as well as their dependencies must be well-defined. Service choreographies are a means to describe the allowed conversations. This article presents a requirements framework for service choreography languages, along which existing choreography languages are assessed. The requirements framework provides the basis for introducing the language BPEL4Chor, which extends the industry standard WS-BPEL with choreography-specific concepts. A validation is provided and integration with executable service orchestrations is discussed.

Local enforceability in interaction Petri nets

In scenarios where a set of independent business partnersengage in complex conversations, global interaction models are a meansto specify the allowed interaction behavior from a global perspective.In these models atomic interactions serve as basic building blocks andbehavioral dependencies are defined between them. Global interactionmodels might not be locally enforceable, i.e. they specify constraints thatcannot be enforced during execution without additional synchronizationinteractions. As this property has only been defined textually so far, thispaper presents a formal definition. For doing so, this paper introducesinteraction Petri nets, a Petri net extension for representing global interactionmodels. Algorithms for deriving the behavioral interface for eachpartner and for enforceability checking are provided.

Formalizing service interactions

Cross-organizational business processes are gaining increased attention these days, especially with the service oriented architecture (SOA) as a realization for business process management (BPM). In SOA, interaction agreements between business partners are defined as choreographies containing common interaction patterns. However, complex interactions are difficult to specify, basically because a formal, common standard supporting all interaction patterns is missing. This paper motivates the use of the π-calculus for formally representing service interaction patterns.

Behavioral consistency for B2B process integration

Interacting services are at the center of attention in businessto-business (B2B) process integration scenarios. Global interaction models specify the interaction behavior of each service and serve as contractual basis for the collaboration. Consequently, service implementations have to be consistent with the specifications. Consistency checking ensures that an implemented service is compatible with other services, i.e. that it can interact successfully with them. This is important in order to avoid deadlocks and guarantee proper termination of a collaboration. Different notions of compatibility between interacting services and consistency between specification and implementation are available but they are typically discussed independently from each other. This paper presents a unifying framework for compatibility and consistency and shows how these two notions relate to one another. Criteria for an optimal consistency relation with respect to a given compatibility relation are presented. Based on these criteria weak bi-simulation is evaluated.

Interaction-centric modeling of process choreographies

With the rise of electronic integration between organizations, the need for a precise specification of interaction behavior increases. Information systems, replacing interaction previously carried out by humans via phone, faxes and emails, require a precise specification for handling all possible situations. Such interaction behavior is described in process choreographies. While many proposals for choreography languages have already been made, most of them fall into the category of interconnection models, where the observable behavior of the different partners is described and then related via message flow. As this article will show, this modeling approach fails to support fundamental design principles of choreographies and typically leads to modeling errors. This motivates an alternative modeling style, namely interaction modeling, for overcoming these limitations. While the main concepts are independent of a concrete modeling language, iBPMN is introduced as novel interaction modeling language. Formal execution semantics are provided and a comprehensive toolset implementing the approach is presented.

BPEL to BPMN: The Myth of a Straight-Forward Mapping

An alignment of the Business Process Execution Language (BPEL) and the Business Process Modelling Notation (BPMN) promises seamless integration of process documentation and executable process definitions. Thus, a lot of research has been conducted on a mapping from BPMN to BPEL. The other perspective of this alignment, i.e. a BPEL-to-BPMN mapping, was largely neglected. This paper presents a condensed discussion of such a mapping and its pitfalls. We illustrate why such a mapping is not as straight-forward as commonly assumed and discuss the gaps to be bridged towards a better alignment of both languages.

Process instantiation

Although several process modeling languages allow one to specify processes with multiple start elements, the precise semantics of such models are often unclear, both from a pragmatic and from a theoretical point of view. This paper addresses the lack of research on this problem and introduces the CASU framework (from Creation, Activation, Subscription, Unsubscription). The contribution of this framework is a systematic description of design alternatives for the specification of instantiation semantics of process modeling languages. We classify six prominent languages by the help of this framework. We validate the relevance of the CASU framework through empirical investigations involving a large set of process models from practice. Our work provides the basis for the design of new correctness criteria as well as for the formalization of Event-driven Process Chains (EPCs) and extension of the Business Process Modeling Notation (BPMN). It complements research such as the workflow patterns.