المسار الحرج - تدبير الطاقات - تخطيط المشاريع .. الحاسبات تعمل

Critical Path - Energy Management - Project Planning .. Computers work

Critical Path

Two events are often linked by different paths that indicate multiple actions with different durations, but all of these actions are necessary to complete the entire process. The critical path consists of the sum of successive paths with the longest durations between the series of events, thus determining the shortest possible period for implementing the project. These factors are clearly shown in the path diagram graph in the figure above.

Time is represented in the graph by horizontal distances, and the filled lines indicate work engagement, while the broken parts of the lines represent idle periods when one of the workers completes his action and waits for another action to finish. These idle periods are known as float and occur in the path that is shorter than other alternative paths between two events. The critical path extends from the first event in the process to the final event without passing through any float. The red line in the figure indicates the critical path in the example mentioned, and shows that the duration of completing the entire process is twenty-nine minutes.

- Energy management

Most actions require different human and material capabilities, such as equipment, raw materials, etc., known as energies. The energy required by the project is shown in a diagram known as a gradient. If we assume in the example of changing a car wheel that each action is simultaneous with another action that requires a single person to accomplish it, the gradient of this process will be as in the figure, and it shows the number of people busy in each unit of time. Note that four people are busy in the fifth minute.

The graph of the critical path diagram after energy management, and the gradient that shows the number of people busy per minute.

It is obvious that the optimal distribution of actions is the one that gives a flat gradient with the least possible number of people, thus achieving the best return from the available human energies. The figure above shows the redistribution of actions in the aforementioned example, and it becomes clear that the new gradient is closer to the ideal gradient than before. While the logical sequence in the new diagram remains the same, and the entire process still takes the same time, some floating actions have been delayed in their start so that one person can complete one action during the idle period of another action. This example shows energy management, i.e. the distribution of actions to achieve the best return from the available capabilities.

- Using the computer

The example of changing a car wheel illustrates the general approach to determining the critical path. The method of determining the critical path is known as time analysis, and requires calculations for different cases, assuming that actions start early or late and end early or late, and calculating the float for each action. All actions that do not have float fall on the critical path.

Since the above example includes only twenty-three actions, the critical path can be determined by simple manual calculations. Large projects may include thousands of actions and hundreds of people, which makes determining the critical path extremely complicated.

The computer performs time analysis and energy management operations at tremendous speed and without error in the logical sequence or in determining the critical path. When the implementation of some operations is delayed, as is the case in most projects, the computer shows the actions that need to be accelerated to return the project to its scheduled time.