Workflow management systems (WfMSs) also known as business process management systems (BPMSs) are increasingly popular in today’s large organizations. In spite of this popularity, many processes are still supported by ad hoc systems based, for example, on spreadsheets and homegrown databases. In particular, there is a lack of flexible process automation approaches that are able to bridge the gap between these ad hoc solutions and large-scale systems. This paper reports on a flexible WfMS and approach that blends formal and informal workflow modeling and execution, thus supporting different types of processes. We validate our work by discussing its design and implementation, and by analyzing its use in four different use cases within Siemens business units. We also discuss the role of action items as important flexibility mechanisms behind our model. Showing its ability to handle exceptions and ad hoc workflows.

Mechatronic systems integrate mechanical, electrical and software subsystems. They are increasingly important in mission-critical infrastructures in different domains including automotive, healthcare, energy and transportation sectors. As such, the adequate testing and validation of such infrastructures are of prime importance. Mechatronic systems testing has been supported by different isolated industrial and research approaches including automated test infrastructures, model-based testing, and test execution engines. While these approaches have individual benefits, they are usually applied in isolation, suffering from different weaknesses. This paper reports on an integrated model-driven approach for mechatronic systems testing, where existing approaches are combined and enhanced. The result is unprecedented levels of automation and testability. We discuss the design and implementation of our approach, illustrating its use with a hybrid calculator example.

Hardware failures occur especially due to external influences, component aging, or faulty interoperability. By testing, faulty components can be localized, allowing for fault isolation or repair. The contract testing strategy from software specifies component interoperability conditions, and systematically creates correspondent tests ensuring the operability of the system. We adapt contract testing to hardware, providing component specification, and monitoring thereof. Contract specification has to be specialized with requirements on the physical environment and component input signals. Contract testing is then executed through the monitoring of the contract parameters. Furthermore, to reason about the external cause of errors, signal faults are categorized. As a case study, we present an communication system. For this system, a contract is defined, and circuits implemented to perform contract testing and fault categorization. Communication faults, related to hardware errors and to sporadic environment disturbance, are injected in the developed system. These faults are completely detected, but can be only partially categorized by the monitoring approach.

In spite of the modularization benefits supported by the Aspect-Oriented programming paradigm, different usability issues have hindered its adoption. The decoupling between aspect definitions and base code, and the compile-time weaving mechanism adopted by different AOP languages, require developers to manage the consistency between base code and aspect code themselves. These mechanisms create opportunities for errors related to aspect weaving invisibility and non-local control characteristics of AOP languages. This paper describes XE (Extreme Editor), an IDE that supports developers in managing these issues in the functional aspect-oriented programming domain.

The focus of our approach to the usability considerations of privacy and security has been on providing people with information they can use to understand the implications of their interactions with a system, as well as, to assess whether or not a system is secure enough for their immediate needs. To this end, we have been exploring two design principles for secure interaction: visualizing system activity and integrating configuration and action. Here we discuss the results of a user study designed as a broad formative examination of the successes and failures of an initial prototype based around these principles. Our response to the results of this study has been twofold. First, we have fixed a number of implementation and usability problems. Second, we have extended our visualizations to incorporate new considerations regarding the temporal and structural organization of interactions.

In our research, we have been concerned with the question of how to make relevant features of security situations visible to users in order to allow them to make informed decisions regarding potential privacy and security problems, as well as regarding potential implications of their actions. To this end, we have designed technical infrastructures that make visible the configurations, activities, and implications of available security mechanisms. This thus allows users to make informed choices and take coordinated and appropriate actions when necessary. This work differs from the more traditional security usability work in that our focus is not only on the usability of security mechanism (e.g., the ease-of-use of an access control interface), but how security can manifest itself as part of people's interactions with and through information systems (i.e., how people experience and interpret privacy and security situations, and are enabled or constrained by existing technological mechanisms to act appropriately). In this paper, we report our experiences designing, developing, and testing two technical infrastructures for supporting this approach for usable security.

Standard client-server workflow management systems are usually designed as client-server systems. The central server is responsible for the coordination of the workflow execution and, in some cases, may manage the activities database. This centralized control architecture may represent a single point of failure, which compromises the availability of the system. We propose a fully distributed and configurable architecture for workflow management systems. It is based on the idea that the activities of a case (an instance of the process) migrate from host to host, executing the workflow tasks, following a process plan. This core architecture is improved with the addition of other distributed components so that other requirements for Workflow Management Systems, besides scalability, are also addressed. The components of the architecture were tested in different distributed and centralized configurations. The ability to configure the location of components and the use of dynamic allocation of tasks were effective for the implementation of load balancing policies.

Standard client-server workflow management systems have an intrinsic scalability limitation: the central server is a bottleneck for large scale applications. It is also a single fault paint that may disable the whole system. We propose a fully distributed architecture for workflow management systems. It is based on the idea that the case (an instance of the process) migrates from host to host, according to the process definition specification, as the corresponding activities are executed. This basic architecture is improved so that other requirements for Workflow Management Systems, besides scalability, are also contemplated. A CORBA-based implementation of such architecture is discussed, with both its limitations and positive points described.