Uncertainty and imprecision: A fuzzy model

In many decision processes, the decision-maker must take decisions on the basis of incomplete, vague or missing information. The author discusses some differences between the concepts of uncertainty and imprecision, and the consequences for the representation of each within a decision model. An approach to the representation of opinion is described and a method for calculating with approximately-known variables is discussed. Some results obtained from the use of these models in a decision model for the design of a high capacity bus system are shown. A comparison is made between design variables calculated by the model, and those actually implemented.<>