Models of Sequential Iterative Development Processes with Conditional Activities

Sequential iterative process is a kind of basic product development process. In the existed ordinary sequential iterative process models, only required main activities are included. However, in standards and practices of some engineering areas, there are conditional activities in developing processes that are only executed under certain conditions. The existed process estimate models are not suitable for this kind of processes. A model of sequential iterative processes with conditional activities is proposed. Three time estimate models for sequential iterative processes with conditional activities are established. The first model does not account for rework amount variation. The second accounts for rework amount variation and the rework impact factors affect the activity durations. In the third model, the rework impact factors affect the remaining time of the rework activities other than the activity durations.