Development of an expert system for construction project networks

A project is defined as a combination of interrelated activities that must beexecuted in a certain order before the entire task can be completed. Theactivities are interrelated in a logical sequence in the sense that someactivities cannot start until others are completed. An activity in a project isusually viewed as a job requiring time and resources for its completion. Ingeneral, a project is a one-time effort; that is, the same sequence ofactivities may not be repeated in the future.The growing complexities of today’s projects have demanded moresystematic and more effective planning techniques with the objective ofoptimizing the efficiency of executing the project. Efficiency ,here, implieseffecting the utmost reduction in the time required to complete the projectwhile accounting for the economic feasibility of using available resources.Project management has evolved as a new field with the development oftwo analytic techniques for planning, scheduling, and controlling ofprojects. These are the critical path method (CPM) and the projectevaluation and review technique (PERT). The two techniques weredeveloped by two different groups almost simultaneously (1956-1958)PERT and CPM are basically time-oriented methods in the sense that theyboth lead to the determination of a time schedule. Although the twomethods were developed independently, they are strikingly similar.Perhaps the most important difference is that originally the time estimatesfor the activities were assumed deterministic in CPM and probabilistic inPERT. Today, PERT and CPM actually comprise one technique and thedifferences are only historical.Project management by PERT-CPM consists of three basic phases:planning, scheduling, and controlling.The planning phase is initiated by breaking down the project into distinctactivities. The time estimates for these activities are then determined, and anetwork diagram is constructed. The establishment of a project plandepends on the type of the project, the experience of the planner and thesize of the project.