August 21 – 26 , 2016, Dagstuhl Seminar 16341
Integrating Process-Oriented and Event-Based Systems
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Background and Motivation
Process-oriented information systems are software systems that execute and manage a process, broadly defined as a coordinated execution of actions to achieve a certain goal. As such, they support Business Process Management (BPM) initiatives. Process-oriented systems have been traditionally used in domains such as business process automation, enterprise application integration, and collaborative work. Recently, there has also been a significant uptake of process-oriented information systems in transportation, logistics, and medical infrastructures -- domains that impose new challenges in terms of system reactivity and adaptability. Here, trends such as sensing of data (e.g., based on RFID technology) and advancing system integration (driven by technical standards such as EPCglobal) represent opportunities to strengthen the event-perspective in process-oriented systems in order to achieve more flexible and comprehensive process control.
Event-based systems, in turn, have been put forward to integrate heterogeneous systems in a flexible and scalable manner by separating communication from application logic. These systems provide interaction models, mechanisms for routing events between components, and techniques for the detection of composite events, i.e., for Complex Event Processing (CEP). Although event-based systems are typically positioned as general-purpose technology, they have found their way into many applications where event generation is comparatively deterministic and follows structured behaviour. In domains such as transportation, logistics, and the medical sector, events handled by event-based systems stem from the execution of processes, which are partially supported by process-oriented information systems. Exploiting the process-perspective, therefore, promises to lead to advancements in the design, analysis, and optimisation of event-based systems.
The increasing overlap of application scenarios that involve concepts and techniques of process-oriented as well as event-based systems, however, is only marginally supported by exchange and convergence of the related research fields. Strong communities have been established for research on either type of system. Yet, due to the missing link between these communities, manifold opportunities for ground-breaking research and broad impact in industry are missed out. Research efforts related to the underlying theory as well as specific platforms are duplicated and similar approaches are developed in both communities.
Breaking this disconnect had been the goal that the seminar aimed to achieve by identifying the links between conceptual models, formal analysis methods, and engineering techniques developed for either type of system.
Given that seminar attendees came from two rather disconnected communities, the first day of the seminar featured four tutorials to establish a joint understanding of essential concepts and terminology. First, Alessandro Margara presented an overview of the basic techniques to manage streams of events. Mathias Weske then gave a primer on BPM, elaborating on the main concepts, models, and the role of events for process management. An advanced view on techniques for event processing was given by Alejandro Buchmann. Stefanie Rinderle-Ma closed this part of the seminar with a tutorial on management, utilisation, and analysis of instance data in distributed process management.
The remainder of the seminar week was centred on break-out sessions, in which participants worked on particular topics on the intersection of process-oriented and event-based systems. In these working groups, participants discussed the relevant state-of-the-art and identified the research challenges under a near-, mid-, or long-term perspective. In addition, there were two sessions in which seminar participants gave a very short overview of their recent research work.
Topics and Key Challenges
The working groups focussed on a diverse set of topics, highlighting the key challenges that need to be addressed:
Event Models for BPM: Semantics of Events and Patterns. Starting from the observation that event models are well-established in both BPM and CEP and that their coupling has obvious benefits, the challenge relates to the question of how events can guide the evolution or adaptation of process instances.
Towards Automatic Event-Based Monitoring of Processes. Event-based monitoring of processes is influenced by the availability of patterns, the consequences of monitoring results, and the integration of contextual information. These dimensions render it particularly challenging to comprehensively discover and utilise patterns for process monitoring.
Patterns and Models for Communication. The communication models underlying an event-based middleware have diverse implications for the interplay of processes and event patterns -- and a major challenge is the identification of requirements that are imposed by process scenarios on communication models.
Choreographies and Inter-Process Correlation. Common languages for the description of interacting processes lack capabilities for the specification of event-based processing. The challenge is to develop a better grounding of choreography languages and enable analysis of the information flow between processes.
Abstraction Levels: Processes versus Events. Observing that methods in BPM mainly proceed top-down, whereas event processing is often approached bottom-up, a key challenge is the identification of the right abstraction level on which concepts and methods shall be integrated.
Context in Events and Processes. The context of a process may influence event processing, and the context as materialised in complex events impacts the execution of a process. Yet, a suitable representation and dynamic evolution of context information is an open research challenge.
Integrated Platforms for BPM & CEP. The integration of traditional BPM or CEP engines promises accelerated application development and lower maintenance cost. To attain this end, the challenge of developing a unified model for events and processes, enabling well-grounded architectural decisions, needs to be addressed.
(Highly) Distributed Processes & The Role of Events. Events and processes can both be handled in a centralised or distributed infrastructure and open challenges relate to the tradeoffs regarding trustworthiness, reliability, and scalability.
Event Data Quality. Event data may be uncertain, which needs to be reflected in processes that are influenced by these events. The challenge is how to capture such uncertainty and make explicit how it influences decision making on the level of the process.
From Event Streams to Process Models and Back. Event patterns and processes are typically concerned with events on different levels of abstractions, which can be bridged only on the basis of a unifying formal model. Further challenges arise from the imprecision of event definitions in processes and the expressiveness of CEP languages when capturing procedural behaviour.
Compliance, Audit, Privacy and Security.Compliance checking of business processes may benefit from CEP systems and BPM tools may be useful to express service level agreements in event-based systems. Challenges, however, are methods for a structured integration of BPM and CEP technology and their alignment with informal compliance requirements.
From the discussions and the exchange of ideas during the workshop, a set of recommendations was able to be distilled in order to materialise the benefits of integrating process-oriented and event-based systems.
Build a community around BPM and CEP. The topics on the intersection of process-oriented and event-based systems provide a rich field for high-impact research. The number and diversity of open research questions call for a long-term research initiative, so that a respective community needs to be built up. To achieve this, it is recommended that joint workshops be initiated at the flagship conferences in either field, the BPM conference and the DEBS conference, and to evaluate potential co-location of the conferences in future.
Start research on integrated models. For many of the aforementioned challenges, the lack of integrated models, in which processes and events are first-class citizens, turns out to be a major issue. Research shall be devoted to creating such models, clarifying which basic notions of events exist, and considering the semantics of distributed event generation.
Facilitate joint research. Joint research is currently hindered not only by the disconnect of the research communities, but also by a lack of a common set of standard concepts in either community. There is a need for concise overviews of the most important concepts and methods in either field, e.g., by means of standard textbooks. Researchers from one field need to be able to quickly gather the level of understanding of the other field that is required for joint research initiatives.
Engage industry.The integration of process-oriented and event-based systems is driven by particular domains, such as logistics, health, and mobility. The prioritisation of challenges and the evaluation of developed solutions critically depends on the involvement of industrial partners from these domains. As such, it is recommended to reach out to industry to develop evaluation scenarios and benchmark datasets. One viable means for this are the research proposals on the EU and national levels that involve BPM and CEP experts from both academia and industry.
Creative Commons BY 3.0 Unported license
David Eyers, Avigdor Gal, Hans-Arno Jacobsen, and Matthias Weidlich
- Data Bases / Information Retrieval
- Semantics / Formal Methods
- Software Engineering
- Process-aware Information Systems
- Event-based Systems
- Distributed Systems