Title
Computing the Expected Execution Time of Probabilistic Workflow Nets.
Abstract
Free-Choice Workflow Petri nets, also known as Workflow Graphs, are a popular model in Business Process Modeling. this paper we introduce Timed Probabilistic Workflow Nets (TPWNs), and give them a Markov Decision Process (MDP) semantics. Since the time needed to execute two parallel tasks is the maximum of the times, and not their sum, the expected time cannot be directly computed using the theory of MDPs with rewards. In our first contribution, we overcome this obstacle with the help of earliest-first schedulers, and give a single exponential-time algorithm for computing the expected time. our second contribution, we show that computing the expected time is #P-hard, and so polynomial algorithms are very unlikely to exist. Further, #P-hardness holds even for workflows with a very simple structure in which all transitions times are 1 or 0, and all probabilities are 1 or 0.5. Our third and final contribution is an experimental investigation of the runtime of our algorithm on a set of industrial benchmarks. Despite the negative theoretical results, the results are very encouraging. In particular, the expected time of every workflow in a popular benchmark suite with 642 workflow nets can be computed in milliseconds.
Year
DOI
Venue
2018
10.1007/978-3-030-17465-1_9
tools and algorithms for construction and analysis of systems
Field
DocType
Volume
Obstacle,Petri net,Suite,Algorithm,Markov decision process,Theoretical computer science,Business process modeling,Probabilistic logic,Workflow,Mathematics,Semantics
Journal
abs/1811.06961
Citations 
PageRank 
References 
0
0.34
0
Authors
3
Name
Order
Citations
PageRank
Philipp Meyer1294.72
Javier Esparza21819147.63
Philip Offtermatt300.34