Showing 2 results for K. Rezaie
M. Rabbani, K. Rezaie, M. M. Lotfi and M. Abadi,
Volume 23, Issue 1 (7-2004)
Abstract
In this paper, a new method for developing a lower bound on exact completion time distribution function of stochastic PERT networks is provided that is based on simplifying the structure of this type of network. The designed mechanism simplifies network structure by arc duplication so that network distribution function can be calculated only with convolution and multiplication. The selection of duplicable arcs in this method differs from that of Dodin’s so that it must be considered a different method. In this method, best duplicable arcs are adopted using a new mechanism. It is proved that duplicating numbers is minimized by this method. The distribution function of this method is a lower bound on exact network distribution function and an upper bound on distribution function of Dodin’s and Kleindorfer’s methods. After the algorithm for the method is presented, its efficiency is discussed and illustration examples will be used to Compare numerical results from this method with those from exact network distribution and Dodin’s method.
Rabbani, K. Rezaie and N. Seid Foroush Lahiji,
Volume 24, Issue 1 (7-2005)
Abstract
Time-cost trade-off is one of the most important subjects in project management and of interest to contractors. The goal of time-cost trade-off is sensivity analysis of project costs to changes in activity duration in order to obtain the best combination of activity duration decrease, in a way that the sum of project costs is minimized. In the heuristics presented in this area, time crashing is on the base of the minimum cost slope of activities. But since projects are usually performed over
long periods, they can be affected by interest rate. In this paper, a new heuristic algorithm is presented in order to obtain the best combination of activity duration decrease while the monetary value is taken into account, with the goal of minimizing the sum of present value of project costs
