Influence Diagrams Involving Time

Student thesis: Master Thesis and HD Thesis

  • Søren Holbech Nielsen
4. term, Computer Science, Master (Master Programme)
IDITs is a representation language for decision problems involving quantitative measures of time. IDITs was, in "Representing Decision Problems Involving Time" by Broe, Jeppesen, and Nielsen, suggested as a representation language, which caters for aspects of time. However, the temporal semantics of elements in IDITs presented in that report are flawed. In this report, we suggest a new set of ordering semantics and a definition of welldefinedness that builds on this new ordering. Furthermore, a method to check an IDIT for welldefinedness is given, and the representation language of IDITs is enhanced to cater for more aspects of time, including varying orderings of decisions.
The introducing report also neglects to present a method for solving decision problems modelled as IDITs, but do suggest a sketch for such a method. In the latter part of this report, we explore the boundaries of this sketch and identify a subset of IDITs that can be solved using this approach. Our method succeeds in handling continuous variables as parents of discrete decisions through exploitation of constraints induced by the nature of time.
Publication dateJun 2003
ID: 61058280