UIB-2014-01 Analyzing the Impact of Process Change Operations on Time-Aware Processes

Autoren: Andreas Lanz, Manfred Reichert

The proper handling of temporal process constraints is crucial in many application domains. Contemporary process-aware information systems (PAIS), however, lack a sophisticated support of time-aware processes. As a particular challenge, the enactment of time-aware processes needs to be flexible as time can neither be slowed down nor stopped. Hence, it should be possible to dynamically adapt time-aware process instances to cope with unforeseen events. In turn, when applying such dynamic changes, it must be re-ensured that the resulting process instances are temporally consistent; i.e., they still can be completed without violating any of their temporal constraints. This paper extends existing process change operations, which ensure soundness of the resulting processes, with temporal constraints. In particular, it provides pre- and post-conditions for these operations that guarantee for the temporal consistency of the changed process instances. Further, we analyze the effects a change has on the temporal properties of a process instance. In this context, we provide a means to significantly reduce the complexity when applying multiple change operations. The presented change operations have been prototypically implemented in the AristaFlow BPM Suite.


UIB-2014-02 Coupling Tableau Algorithms for the DL SROIQ with Completion-Based Saturation Procedures

Autoren: Andreas Steigmiller, Birte Glimm, Thorsten Liebig

Nowadays, saturation-based reasoners for the OWL EL profile are able to handle large ontologies such as SNOMED very eciently. However, saturation-based reasoning procedures become incomplete if the ontology is extended with axioms that use features of more expressive Description Logics, e.g., disjunctions. Tableau-based procedures, on the other hand, are not limited to a specific OWL profile, but even highly optimised reasoners might not be ecient enough to handle large ontologies such as SNOMED. In this paper, we present an approach for tightly coupling tableau- and saturation-based procedures that we implement in the OWL DL reasoner Konclude. Our detailed evaluation shows that this combination significantly improves the reasoning performance on a wide range of ontologies.


UIB-2014-03 Conditioned Belief Propagation Revisited

Autoren: Thomas Geier, Felix Richter, Susanne Biundo

Belief Propagation (BP) applied to cyclic problems is a well known approximate inference scheme for probabilistic graphical models. To improve its accuracy, Conditioned Belief Propagation (CBP) has been proposed, which splits a problem into subproblems by conditioning on variables, applies BP to subproblems, and merges the results to produce an answer to the original problem. In this work, we propose a reformulated version of CBP that exhibits anytime behavior and allows for more speci c tuning by formalizing a further aspect of the algorithm through the use of a leaf selection heuristic. We propose several simple and easy to compute heuristics and demonstrate their performance using an empirical evaluation on randomly generated problems.


UIB-2014-04 Statistical Computing 2014

Autoren: HA Kestler, M Schmid, L Lausser, JM Kraus (eds)

46. Arbeitstagung der Arbeitsgruppen Statistical Computing (GMDS/IBS-DR), Klassifikation und Datenanalyse in den Biowissenschaften (GfKl). 20.07.-23.07.2014, Schloss Reisensburg (Günzburg)


UIB-2014-05 Simple Temporal Networks with Partially Shrinkable Uncertainty (Extended Version)

Autoren: Andreas Lanz, Roberto Posenato, Carlo Combi, Manfred Reichert

The Simple Temporal Network with Uncertainty (STNU) model focuses on the representation and evaluation of temporal constraints on time-point variables (timepoints), of which some (i.e., contingent timepoints) cannot be assigned (i.e., executed by the system), but only be observed. Moreover, a temporal constraint is expressed as an admissible range of delays between two timepoints. Regarding the STNU model, it is interesting to determine whether it is possible to execute all the timepoints under the control of the system, while still satisfying all given constraints, no matter when the contingent timepoints happen within the given time ranges (controllability check). Existing approaches assume that the original contingent time range cannot be modified during execution. In real world, however, the allowed time range may change within certain boundaries, but cannot be completely shrunk. To represent such possibility more properly, we propose Simple Temporal Network with Partially Shrinkable Uncertainty (STNPSU) as an extension of STNU. In particular, STNPSUs allow representing a contingent range in a way that can be shrunk during run time as long as shrinking does not go beyond a given threshold. We further show that STNPSUs allow representing STNUs as a special case, while maintaining the same efficiency for both controllability checks and execution.


UIB-2014-06 An Operational Semantics for the Extended Compliance Rule Graph Language

Autoren: David Knuplesch, Manfred Reichert

A challenge for any enterprise is to ensure conformance of its business processes with imposed compliance rules. Usually, the latter may constrain multiple perspectives of a business process, including control ow, data, time, resources, and interactions with business partners. Like for process modeling, intuitive visual languages have been proposed for specifying compliance rules. However, business process compliance cannot completely be decided at design time, but needs to be monitored during run time as well. In previous work we introduced the extended Compliance Rule Graph (eCRG) language that enables the visual monitoring of business process compliance regarding the control ow, data, time, and resource perspectives as well as the interactions a process has with business partners. This technical report introduces an operational semantics of the eCRG language. In particular, the state of a visual compliance rule is reected through markings and annotations of an eCRG. The proposed operational semantics not only allows detecting compliance violations at runtime, but visually highlights their causes as well. Finally, it allows providing recommendations to users in order to proactively ensure for a compliant continuation of a running business process.