Cost/time estimation in flat plate processing (FPP) is a complex system of
man-work-environment-organisation. As the share and impact of physical, psy
chological, personal, and other characteristics of humans (non-process fact
ors) in this complex system becomes larger, the state of FPP time estimatio
n changes from well-defined to ill-defined (uncertain). In this paper, the
effect of process and non-process factors on the activity time variation ar
e discussed and a multivalued fuzzy set (MVFS) is used to model the uncerta
inty activity time/cost estimation in FPP. Emphasis is placed on modelling
of nonrandom uncertainties using fuzzy sets.