Noname manuscript No. (will be inserted by the editor) A Dynamic Default Revision Mechanism for Speculative Computation Tiago Oliveira · Ken Satoh · Paulo Novais · Jos´ e Neves · Hiroshi Hosobe Received: date / Accepted: date Abstract In this work a default revision mechanism is introduced into Spec- ulative Computation to manage incomplete information. The default revision is supported by a method for the generation of default constraints based on Bayesian Networks. The method enables the generation of an initial set of defaults which is used to produce the most likely scenarios during the compu- tation, represented by active processes. As facts arrive, the Bayesian Network is used to derive new defaults. The objective with such a new dynamic mecha- nism is to keep the active processes coherent with arrived facts. This is achieved by changing the initial set of default constraints during the reasoning process in Speculative Computation. A practical example in clinical decision support is described. Keywords Default Revision, Incomplete Information, Speculative Compu- tation, Bayesian Networks. 1 Introduction In order to tackle situations of problem solving and decision making in which cases of incomplete information may occur, a framework of Speculative Com- T. Oliveira · P. Novais · J. Neves Algoritmi Research Centre/Department of Informatics, University of Minho Braga, Portugal E-mail: {toliveira,pjon,jneves}@di.uminho.pt K. Satoh National Institute of Informatics, Sokendai University Tokyo, Japan E-mail: ksatoh@nii.ac.jp H. Hosobe Department of Digital Media, Hosei University Tokyo, Japan E-mail: hosobe@hosei.ac.jp