Uncertainty network planning methodology based on the connection number a+bi+cj

The connection number a+bi+cj, a new kind of number introduced in set pair analysis (SPA) theory, was used in uncertain network planning methodology to represent the uncertainty and delay of working procedure time. It is caused by random, fuzzy, indeterminate-known or unforeseen factors and unexpected incident in a project. The concepts of primary critical paths, secondary critical paths and third critical paths with the classifying method of critical paths in uncertainty environment were introduced. A new uncertainty network planning method is constructed, which is different from the traditional concept and more consistent with the practical application. The new concept can obtain three different sets of critical paths instead of only one critical path obtained by traditional one. The illustrating examples given in this paper indicate that the new method can provide more useful information for the finish time forecasting and controlling of a project.