On the Complexity of Temporal Controllabilities for Workflow Schemata

Recently, different kinds of "controllability" have been proposed for workflow schemata modeling real world processes made of tasks and coordination activities. Temporal controllability is the capability of executing a workflow for all possible durations of all tasks satisfying all temporal constraints. Three different types of controllability are possible -- strong controllability, history-dependent controllability, and weak controllability -- and a general exponential-time algorithm to determine the kind of controllability has been proposed. In this paper we analyze the computational complexity of the temporal controllability problem to verify the quality of proposed algorithms. We show that the weak controllability problem is \coNP-complete, while strong controllability problem is in \u3a3_2^P and it is coNP-hard. Regarding the history-dependent controllability problem, we are able to show that it is a PSPACE problem but further research is required to determine its hardness characterization

Flexible temporal constraint management in modularized processes

Managing temporal process constraints in modularized processes is an important task, both during the design, as it allows the reuse of temporal (child) process models, and during the checking of temporal properties of processes, as it avoids the necessity of ‘‘unfolding’’ child processes within the main process model. Taking into account the capability of providing modular solutions, modeling and checking temporal features of processes is still an open problem in the context of process-aware information systems. In this paper, we present and discuss a novel approach to represent flexible temporal constraints in modularized time-aware BPMN process models. To support temporal flexibility, allowed task durations are represented through guarded ranges that allow a limited (guarded) restriction of task durations during process execution if it is necessary to guarantee the satisfaction of all temporal constraints. We, then, propose how to derive a compact representation of the overall temporal behavior of such time-aware BPMN models. Such compact representation of child processes allows us to check the dynamic controllability (DC) of a parent timeaware process model without ‘‘unfolding’’ the child process models. Dynamic controllability guarantees that process models can have process instances (i.e., executions) satisfying all the temporal constraints for any possible combination of allowed durations of tasks and child processes. Possible approaches for even more flexibility by solving some kinds of DC violations are then introduced. We use a real process model from a healthcare domain as a motivating example, and we also present a proof-of-concept prototype confirming the concrete applicability of the solutions we propose, followed by an experimental evaluation

Tackling Dierent Business Process Perspectives

Business Process Management (BPM) has emerged as a discipline to design, control, analyze, and optimize business operations. Conceptual models lie at the core of BPM. In particular, business process models have been taken up by organizations as a means to describe the main activities that are performed to achieve a specific business goal. Process models generally cover different perspectives that underlie separate yet interrelated representations for analyzing and presenting process information. Being primarily driven by process improvement objectives, traditional business process modeling languages focus on capturing the control flow perspective of business processes, that is, the temporal and logical coordination of activities. Such approaches are usually characterized as \u201cactivity-centric\u201d. Nowadays, activity-centric process modeling languages, such as the Business Process Model and Notation (BPMN) standard, are still the most used in practice and benefit from industrial tool support. Nevertheless, evidence shows that such process modeling languages still lack of support for modeling non-control-flow perspectives, such as the temporal, informational, and decision perspectives, among others. This thesis centres on the BPMN standard and addresses the modeling the temporal, informational, and decision perspectives of process models, with particular attention to processes enacted in healthcare domains. Despite being partially interrelated, the main contributions of this thesis may be partitioned according to the modeling perspective they concern. The temporal perspective deals with the specification, management, and formal verification of temporal constraints. In this thesis, we address the specification and run-time management of temporal constraints in BPMN, by taking advantage of process modularity and of event handling mechanisms included in the standard. Then, we propose three different mappings from BPMN to formal models, to validate the behavior of the proposed process models and to check whether they are dynamically controllable. The informational perspective represents the information entities consumed, produced or manipulated by a process. This thesis focuses on the conceptual connection between processes and data, borrowing concepts from the database domain to enable the representation of which part of a database schema is accessed by a certain process activity. This novel conceptual view is then employed to detect potential data inconsistencies arising when the same data are accessed erroneously by different process activities. The decision perspective encompasses the modeling of the decision-making related to a process, considering where decisions are made in the process and how decision outcomes affect process execution. In this thesis, we investigate the use of the Decision Model and Notation (DMN) standard in conjunction with BPMN starting from a pattern-based approach to ease the derivation of DMN decision models from the data represented in BPMN processes. Besides, we propose a methodology that focuses on the integrated use of BPMN and DMN for modeling decision-intensive care pathways in a real-world application domain

Controlling Time-Awareness in Modularized Processes (Extended Version)

The proper handling of temporal process constraints is crucial in many application domains. However, a sophisticated support of time-aware processes is still missing in contemporary information systems. As a particular challenge, temporal constraints must be also handled for modularized processes (i.e., processes comprising subprocesses), enabling the re-use of process knowledge as well as the modular design of complex processes. This paper focuses on the representation and support of time-aware modularized processes. In particular, we present a sound and complete method to derive the duration restrictions of a time-aware (sub-)process in such a way that its temporal properties are completely specified. We then show how this characterization of a process can be utilized when re-using it as a subprocess within a modularized process

Managing time-awareness in modularized processes

Managing temporal process constraints in a suitable way is crucial for long-running business processes in many application domains. However, proper support of time-aware processes is still missing in contemporary information systems. This paper tackles a particular challenge existing in this context, namely the handling of temporal constraints for modularized processes (i.e., processes comprising subprocesses), which shall enable both the reuse of process knowledge and the modular design of complex processes. In detail, this paper focuses on the representation and support of time-aware modularized processes in process-aware information systems. To this end, we present a sound and complete method to derive the duration restrictions of a time-aware (sub-)process in such a way that its temporal properties are completely speci\ufb01ed. We then show how this characterization of a process can be utilized when reusing it as a subprocess within a modularized process. As a motivating example, we consider a compound process from healthcare. Altogether the proper handling of temporal constraints for modularized processes is crucial for the enhancement of time- and process-aware information systems

A modular approach to the specification and management of time duration constraints in BPMN

The modeling and management of business processes deals with temporal aspects both in the inherent representation of activity coordination and in the specification of activity properties and constraints. In this paper, we address the modeling and specification of constraints related to the duration of process activities. In detail, we consider the Business Process Model and Notation (BPMN) standard and propose an approach to define re-usable duration-aware process models that make use of existing BPMN elements for representing different nuances of activity duration at design time. Moreover, we show how advanced event-handling techniques may be exploited for detecting the violation of duration constraints during the process run-time. The set of process models specified in this paper suitably captures duration constraints at different levels of abstraction, by allowing designers to specify the duration of atomic tasks and of selected process regions in a way that is conceptually and semantically BPMN-compliant. Without loss of generality, we refer to real-world clinical working environments to exemplify our approach, as their intrinsic complexity makes them a particularly challenging and rewarding application environment

Managing Decision Tasks and Events in Time-Aware Business Process Models

Time-aware business process models capture processes where temporal properties and constraints have to be suitably managed to achieve proper completion. Temporal aspects also constrain how decisions are made in processes: while some constraints hold only along certain paths, decision outcomes may be restricted to satisfy temporal constraints. In this paper, we present time-aware BPMN processes and discuss how to: (i) add temporal features to process elements, by considering also the impact of events on temporal constraint management; (ii) characterize decisions based on when they are made and used within a process; (iii) specify and use two novel kinds of decisions based on how their outcomes are managed; (iv) deal with intertwined temporal and decision aspects of time-aware BPMN processes to ensure proper execution