Work planning always begins with determining the number of tasks responsible for their implementation and the time required to complete it. In project management, such schemes are simply necessary. Firstly, in order to understand what total time will be spent, and secondly, to know how to plan resources. This is what project managers do, they primarily build the network. An example of a possible situation will be considered below.
The management of the advertising agency decided to release a new advertising product for its customers. The company’s employees were assigned the following tasks: to consider the ideas of advertising brochures, give arguments in favor of one or another option, create a layout, prepare a draft contract for customers and send all the information to the management for consideration. In order to inform customers, it is necessary to carry out a newsletter, put up posters and call all the companies available in the database.
In addition, the chief executive drew up a detailed plan of all necessary actions, appointed responsible employees and set the time.
Let's start building a network. An example has the data shown in the following figure:
Before you create a network diagram, you must create a matrix. Charting begins at this point. Imagine a coordinate system in which vertical values correspond to i (the initial event) and horizontal lines correspond to j (the final event).
We begin to fill in the matrix, focusing on the data in Figure 1. The first work has no time, so it can be neglected. Let's consider the second in more detail.
The starting event starts at 1 and ends at the second event. The duration of the action is 30 days. This number is entered in the cell at the intersection of 1 row and 2 columns. In a similar way, we display all the data that is presented in the figure below.
The main elements used for network graphics
The construction of graphs begins with the designation of the theoretical foundations. Consider the basic elements required to create a model:
- Any event is indicated by a circle in the middle of which is a figure corresponding to the order of actions.
- The work itself is an arrow leading from one event to another. Above the arrow write the time required to complete it, and under the arrow indicate the responsible person.
Work can be performed in three states:
- Acting is an ordinary action, the completion of which requires the expenditure of time and resources.
- Waiting is a process during which nothing happens, but it takes time to move from one event to another.
- Fictitious work is a logical connection between events. It does not require either time or resources, but in order not to interrupt the network, it is indicated by a dashed line. For example, preparing grain and preparing bags for it are two separate processes, they are not connected in series, but their connection is needed for the next event - packaging. Therefore, another circle is distinguished, which is connected by a dotted line.
Basic principles of construction
The rules for building network diagrams are as follows:
- All events have a beginning and an end.
- Only the first event may not go arrows, and only from the last they do not go.
- All events without exception should be connected by sequential work.
- The graph is built strictly from left to right in sequential order.
- Two events can be connected only by one work. You can not put two arrows; if you need to do two work, then enter a dummy with a new event.
- There must be no dead ends on the network. The situation indicated in Figure 3 must not be allowed.
- The formation of cycles and closed loops must not be allowed.
Networking construction. Example
Let's go back to the original example and try to draw a network diagram using all the data indicated earlier.
We start from the first event. Two come out of it - the second and third, which are connected in the fourth. Further, everything goes sequentially until the seventh event. Three works come out of it: the eighth, ninth and tenth. We will try to display everything:
This is not all network building. The example continues. Next, you need to calculate critical moments.
The critical path is the longest time taken to complete a task. In order to calculate it, you need to add up all the highest values of sequential actions. In our case, these are works 1-2, 2-4, 4-5, 5-6, 6-7, 7-8, 8-11. Summarize:
30 + 2 + 2 + 5 + 7 + 20 + 1 = 67 days
Thus, the critical path is 67 days.
If such time for the project does not suit the management, it must be optimized according to the requirements.
Today, few project managers manually draw diagrams. The program for building network diagrams is a simple and convenient way to quickly calculate the time spent, determine the order of work and appoint performers.
Briefly consider the most common programs:
- Microsoft Project 2002 is an office product in which it is very convenient to draw diagrams. But carrying out the calculations is a little inconvenient. In order to perform even the simplest action, you need a considerable amount of knowledge. When downloading the program, take care of acquiring instructions for using it.
- SPU v2.2. Very common free software. Rather, it’s not even a program, but a file in the archive, which does not require installation to use. Initially, it was developed for the final work of one student, but it turned out to be so useful that the author posted it on the network.
- NetGraf is another development of a domestic specialist from Krasnodar. It is very light, easy to use, does not require installation and a huge amount of knowledge about how to manage it. A plus is that it supports the import of information from other text editors.
- Often you can find just such an instance - Borghiz . Little is known about the developer, as well as how to use the program. But by the primitive method of "poking" it can be mastered. The main thing is that it works.