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Abstract. Formal specification and operational support of time constraints constitute fundamental challenges for any enterprise information system. Although temporal constraints play an important role in the context of long-running business processes, time support is very limited in existing process management systems. By contrast, different kinds of planning tools (e.g., calendar systems and project management tools) provide more sophisticated facilities for handling task-related time constraints, but lack an operational support for business processes. This paper presents a set of 10 time patterns to foster the systematic comparison of these different technologies in respect to time management. The proposed patterns are all based on empirical evidence from several large case studies. In addition, we provide an in-depth evaluation of selected process management systems, calendar systems and project management tools based on the suggested patterns. The presented work will not only facilitate comparison of these different technologies in respect to their support of time constraints, but also make evident that their integration offers promising perspectives in respect to time support for long-running business processes.

Abstract. Declarative process models are increasingly used since they fit better with the nature of flexible process-aware information systems and the requirements of the stakeholders involved. When managing business processes, in addition, support for representing time and reasoning about it becomes crucial. Given a declarative process model, users may choose among different ways to execute it, i.e., there exist numerous possible enactment plans, each one presenting specific values for the given objective functions (e.g., overall completion time). This paper suggests a method for generating optimized enactment plans (e.g., plans minimizing overall completion time) from declarative process models with explicit temporal constraints. The latter covers a number of well-known workflow time patterns. The generated plans can be used for different purposes like providing personal schedules to users, facilitating early detection of critical situations, or predicting execution times for process activities. The proposed approach is applied to a range of test models of varying complexity. Although the optimization of process execution is a highly constrained problem, results indicate that our approach produces a satisfactory number of suitable solutions, i.e., solutions optimal in many cases.

We present an operational semantics for time-aware business processes, that is, processes modeling the execution of business activities, whose durations are subject to linear constraints over the integers. We assume that some of the durations are controllable, that is, they can be determined by the organization that enacts the process, while others are uncontrollable, that is, they are determined by the external world. Then, we consider controllability properties, which guarantee the completion of the enactment of the process, satisfying the given duration constraints, independently of the values of the uncontrollable durations. Controllability properties are encoded by quantified reachability formulas , where the reachability predicate is recursively defined by a set of Constrained Horn Clauses (CHCs). These clauses are automatically derived from the operational semantics of the process. Finally, we present two algorithms for solving the so called weak and strong controllability problems. Our algorithms reduce these problems to the verification of a set of quantified integer constraints, which are simpler than the original quantified reachability formulas, and can effectively be handled by state-of-the-art CHC solvers.

Summary. Companies increasingly adopt process-aware information systems (PAISs) to model, enact, monitor, and evolve their business processes. Although the proper handling of temporal constraints (e.g., deadlines and minimum time lags between activities) is crucial for many application domains, existing PAISs vary significantly regarding the support of the temporal perspective of a business process. In previous work, we introduced characteristic time patterns for specifying the temporal perspective of PAISs. However, time-aware process schemas might be complex and hard to understand for end-users. To enable their proper visualization, therefore, this paper introduces an approach for transforming time-aware process schemas into enhanced Gantt charts. Based on this, a method for creating personalized process schedules using process views is suggested. Overall, the presented approach enables users to easily understand and monitor time-aware processes in PAISs.