Fuzzy stochastic risk-based decision analysis with the mobile offshore base as a case study

The Office of Naval Research in a feasibility study of a mobile offshore base (MOB) has proposed several concepts for very large ocean structures and will make risk informed assessments of alternative concepts. Using the MOB as a case study, this paper provides methodology for fuzzy-stochastic cost and schedule risk-based decision analysis of alternative MOB hull construction concepts. The uncertainty intrinsic in a system influences requisite risk-based decision analysis methodology. Probabilistic, ambiguous, or aleatory uncertainty entails stochastic methods. Cognitive, vague, or epistemic uncertainty requires fuzzy sets and logic. Simulation is used to overcome difficulty, or known intractability, associated with mathematical formulation of analytical models of complex engeering systems. This paper provides generalized fuzzy-stochastic risk-based decision analysis methodology and demonstrates fuzzy set quantification of MOB subjective information. Fuzzy-Bayesian updating of the state-of-knowledge of MOB cost and schedule information as it is piecewise accumulated is also discussed.