Cost and Time Scaled Networks: Graphical Model

The CPM type network solution developed in this paper extends the known time-scaled representation of networks, which uses the horizontal axis as a time scale, by incorporating the cost of the activities using the vertical axis for cost. Each activity within the network is described in its entirety, including its normal and crash characteristics and its time-cost trade-off curve which may be of any shape. A simple graphical procedure to generate, for a given project, the minimum cost crash solution and the optimum time-cost trade-off curve is outlined. The method applies to condensed networks or to small projects where computerized techniques would be too costly and otherwise would not be followed. As it is graphical, it can be used as an effective means of communication and to implement at the less-specialized user's level, the principles involved in the planning and control of projects.