Correctness of services and their composition

We study correctness of services and their composition and investigate how the design of correct service compositions can be systematically supported. We thereby focus on the communication protocol of the service and approach these questions using formal methods and make contributions to three scenarios of SOC.Wir studieren die Korrektheit von Services und Servicekompositionen und untersuchen, wie der Entwurf von korrekten Servicekompositionen systematisch unterstützt werden kann. Wir legen dabei den Fokus auf das Kommunikationsprotokoll der Services. Mithilfe von formalen Methoden tragen wir zu drei Szenarien von SOC bei

Correctness of services and their composition

We study correctness of services and their composition and investigate how the design of correct service compositions can be systematically supported. We thereby focus on the communication protocol of the service and approach these questions using formal methods and make contributions to three scenarios of SOC.Wir studieren die Korrektheit von Services und Servicekompositionen und untersuchen, wie der Entwurf von korrekten Servicekompositionen systematisch unterstützt werden kann. Wir legen dabei den Fokus auf das Kommunikationsprotokoll der Services. Mithilfe von formalen Methoden tragen wir zu drei Szenarien von SOC bei

Data perspective in process choreographies : modeling and execution

Process choreographies - communication between different organizations to exchange information - is part of daily business. While the correct ordering of exchanged messages can be modeled and enacted with current choreography techniques, no approach exists to describe the data perspective for a successful process choreography. In this paper, we describe an entirely model-driven approach for BPMN, the industry standard, to include the data perspective while maintaining control flow aspects by utilizing a recent concept to enact data dependencies in internal processes. This work provides a modeling guideline with the require artifacts and their operational semantics to allow automatic choreography enactment covering data retrieval, transformation, and correlation. We show applicability of our approach by an implementation for the Camunda BPM platform, a java-based process engine, and validate it with the service interaction patterns. Keywords: Process Modeling, Data Modeling, Process Choreographies, Process Enactment, BPMN, SQ

Abschlussbericht des Verbundprojekts Tools4BPEL

Unternehmensübergreifende Geschäftsprozesse werden zunehmend nach dem Paradigma der Services organisiert. Dabei stellen sich Fragen nach der Komponierbarkeit, Fehlerbehandlung, sowie der Rücksetzbarkeit (Kompensation) im Fehlerfall. In diesem Vorhaben werden Methoden und Werkzeuge zum Umgang mit solchen Fragen entwickelt und am Beispiel der Geschäftsprozess-Modellierungssprache BPEL und im Modellierungswerkzeug der Firma MEGA international erprobt. Es wurde zum einen der Übersetzer BPEL2oWFN entwickelt, der anhand einer Petrinetzsemantik für BPEL einen BPEL-Prozess in ein (offenes) Petrinetz transformiert. Zum anderen wurden Korrektheitskriterien (wie Bedienbarkeit und Verhaltenskompatibilität) für Services erarbeitet, Algorithmen zu ihrer Überprüfung entworfen und in Fiona implementiert. Die Algorithmen sind Petrinetz-basiert. Damit spielen Übersetzung und Analyse eng zusammen und ein vorhandener BPEL-Prozess kann auf bspw. Bedienbarkeit hin untersucht werden. In diesem Vorhaben wurden die Modellierungssprache BPEL4Chor, Choreographie-Erweiterungen für BPMN entwickelt, sowie die Transformation von BPMN nach BPEL angepasst, um den Weg von BPMN nach BPEL4Chor zu unterstützen. Weiterhin wurden Konzepte entwickelt, wie sich partner-übergreifende Fehlerbehandlung, Rücksetzbarkeit, sowie die Autonomie der Partner mittels BPEL4Chor darstellen lassen. BPEL4Chor kann als Standardsprache zur Spezifikation von Protokollen, die zwischen mehreren Partnern ablaufen, verwendet werden. Durch seine enge Verbindung mit BPEL kann BPEL4Chor sehr gut als Startpunkt für eine Webservice-Lösung verwendet werden

Data-Aware Interaction in Distributed and Collaborative Workflows: Modeling, Semantics, Correctness

IT support for distributed and collaborative workflows and related interactions between business partners is becoming increasingly important. For modeling such partner interactions as flow of message exchanges, different top-down approaches, covered under the term interaction modeling, are provided. Like for workflow models, correctness constitutes a fundamental challenge for interaction models as well; e.g., to ensure the boundedness and absence of deadlocks and lifelocks. Due to their distributed execution, in addition, interaction models should be message-deterministic and realizable, i.e., the same conversation (i.e. sequence of messages) should always lead to the same result, and it should be ensured that partners always have enough information about the messages they must or may send in a given context. So far, most existing approaches have addressed correctness of interaction models without explicitly considering the data exchanged through messages and used for routing decisions. However, data support is crucial for collaborative workflows and interaction models respectively. This paper therefore enriches interaction models with the data perspective. In particular, it defines the behavior of data-aware interaction models based on Data-Aware Interaction Nets, which use elements of both Interaction Petri Nets and Workflow Nets with Data. Finally, formal correctness criteria for Data-Aware Interaction Nets are derived, guaranteeing the boundedness and absence of deadlocks and lifelocks, and ensuring message-determinism as well as realizability

Choreography-based business process consolidation in one-to-many interactions

In different real world scenarios the big companies can acquire other companies, or the company can insource some of its own organizational units residing abroad to increase security and control on those units, also achieve minimization of transaction costs. In these scenarios business processes of partner companies need to be consolidated with each other. Interaction of the business processes of partner companies can be modeled by choreographies. The related works contain an approach for consolidation of the business processes which are represented in choreography with only one instance per process type. In other words, the related works only contain consolidation solution for one-to-one interaction scenarios. However, this thesis presents a concept for choreography based business process consolidation in one-to-many interaction scenarios, where one process interacts with multiple instances of another process. In particular, the number of involved instances is unknown at design time, and it only becomes known at run time of choreography. Flight ticket booking choreography is used as a motivation scenario, where it is assumed that number of involved airlines is not known in advance. On the whole, the process consolidation approach is extended for supporting consolidation of multi-instance partner processes into one merged process

Modeling Service Choreographies with Rule-enhanced Business Processes

The participation at EDOC 2010 was overwhelming in every positive sense, and I am very thankful to the committee for this award. Our presentation was received highly positive and triggered several questions. The questions were mainly about the relations of our work with the use of ontology and vocabulary representation languages, and our plans for developing executable models rather than generating code from models. In fact, this was already in line with our previous plans and research directions. Some of these discussions even continued during the following days. In particular, we had plans for two concrete collaborations. One is related to the development of a formal semantics of the rBPMN languages by using process algebra, that is, by using the mCRL2 language in particular. Moreover, we also created a common plan for integration of semi-structured English language for defining business rules and vocabularies. This will also allow us to have a more effective way to capture rules in rBPMN process models. Moreover, our presentation of the rBPMN editor, as an practical implementation tool for the work with the rBPMN language received a special attention, and several researchers have already approached us to establish research collaboration and/or to use our tool, which is now publically available. The overall experience was also extremely valuable. The program of the conference covered nearly all of the diverse topics in enterprise computing. That is, the selected papers cover engineering aspects in many phases of development life cycle of enterprise systems, especially those designed for distributed environments. I have also delivered a keynote at the VORTE 2010 workshop with the audience with was the largest of all workshop keynotes at the conference. The participants very positively received my insights. In a very interactive session, we discussed some of the main research challenges important for better integration of business rules and business process modeling languages.The research community has so far mainly focused on the problem of modeling of service orchestrations in the domain of service composition, while modeling of service choreographies has attracted less attention. The following challenges in choreography modeling are tackled in this paper: i) choreography models are not well-connected with the underlying business vocabulary models. ii) there is limited support for decoupling parts of business logic from complete choreography models. This reduces dynamic changes of choreographies; iii) choreography models contain redundant elements of shared business logic, which might lead to an inconsistent implementation and incompatible behavior. Our proposal – rBPMN – is an extension of a business process modeling language with rule and choreography modeling support. rBPMN is defined by weaving the metamodels of the Business Process Modeling Notation and REWERSE Rule Markup Language. To evaluate our proposal, we use service-interaction patterns and compare our approach with related solutions

A Formal Framework for Data-Aware Process Interaction Models

IT support for distributed and collaborative workflows as well as related interactions between business partners are becoming increasingly important. For modeling such partner interactions as flow of message exchanges, different topdown approaches, covered under the term interaction modeling, are provided. Like for workflow models, correctness constitutes a fundamental challenge for interaction models; e.g., to ensure the boundedness and absence of deadlocks and lifelocks. Due to their distributed execution, in addition, interaction models should be message-deterministic and realizable, i.e., the same conversation (i.e. sequence of messages) should always lead to the same result, and it should be ensured that partners always have enough information about the messages they must or may send in a given context. So far, most existing approaches have addressed correctness of interaction models without explicitly considering the data exchanged through messages and used for routing decisions. However, data support is crucial for collaborative workflows and interaction models respectively. This technical report enriches interaction models with the data perspective. In particular, it defines the behavior of data-aware interaction models based on Data- Aware Interaction Nets, which use elements of both Interaction Petri Nets and Workflow Nets with Data. Finally, formal correctness criteria for Data-Aware Interaction Nets are derived, guaranteeing the boundedness and absence of deadlocks and lifelocks, and ensuring message-determinism as well as realizability

Guiding the Creation of Choreographed Processes with Multiple Instances Based on Data Models

Choreography in business processes is used as a mechanism to communicate various organizations, by providing a method to isolate the behaviour of each part and keeping the privacy of their data. Nev ertheless, choreography diagrams can also be necessary inside an orga nization when a single instance of a process needs to interact and be synchronized with multiple instances of another process simultaneously. The description, by business experts, and the implementation, by devel opers, of these choreographed models are highly complex, especially when the activities involved in the processes exchange various data objects and with different cardinalities. We propose the automatic detection of the synchronization points, when a choreographed process model is needed. The choreography will be derived from the analysis of the process model, data objects consumed and generated through the process, and the data conceptual model that relates the data objects. A graphical tool has been developed to support where the synchronization points must be included, helping to decide about the patterns that describe how a single model can be transformed into a choreographed model.Ministerio de Ciencia y Tecnología TIN2015-63502-C3-2-