The Programming and the Control of the Complex Works Execution

The programming and the control of the complex works execution

2.1. General presentation

The co-ordination, one of the conducting attributes, is responsible with the correlation of different activities that are carried out in organisations.

The co-ordination of both basic production -production programming- and auxiliary activities - maintenance programming- is necessary in the domain of the Production function. In the case of the Research & Development function one may consider the co-ordination of both applied research activities - products, technologies- and the activities of building chemical installations.

Generally, the modern industrial production imposes programming, meaning the time and space considered for each worker of complex, non-repetitive works, made up of many distinct activities, in a complex interdependence.

There are many methods of programming , but they can be mainly classified into two categories:

-graphical methods: simple, used in the case of a small number of activities

-mathematical methods from the domain of operational research, more “powerful”, used in the case of complex activities that impose the automatic processing of data.

The most known graphical method is Gantt method, presented in a simple form in part 2.2.

The mathematical methods of programming used in the complex activities are based on graph theories. The most known are:

-CPM method (Critical Path Method)

-PERT method (Program Evaluation and Review Technique)

and are presented in a simple form in part 2.3.

The programs resulted by applying these methods show the date line of each activity that belongs to a work and are used for the inspection and control of the plan fulfilment.

2.2. Gantt graph

The application of this method consists in the a table elaboration, in which one may represent the activities sequence, taking into account the relations among them and their duration. The activities are graphically represented by bands that are equal in length with their duration. The graph is made up in a relative time scale, that has as origin the beginning of the first activity. When the moment of “start activity” is established one may pass to the calendar time by considering all the non-work intervals (work shifts, holidays).

The next data must be known for this method development:

-activities duration, in adequate time units

-what activity is/are preceding to others

The application of the method is presented taking as an example a stirring tank from the mechanical - energetical department from a large chemical industrial unit. The characteristics are shown in the table 2.1.

Table 2.1.

Sequence and duration for designing and executing a stirring tank.

No Activity name Symbol Previous activities Duration

zile

1 The establishment of the technologic parameters A - 7

2 The establishment of the mechanic parameters B - 9

3 Technological design C A 10

4 Mechanical designing D B, C 9

5 Assent and approval of the project E D 3

6 Elaboration of the execution drawings F D 15

7 Components execution G E, F 29

8 Reductor and engine acquisition H E 21

9

Equipment assemblage and mechanical trial I G, H 5

In the figure 2.1 the Gantt graph is presented for the mentioned work; we firstly have to consider the relative time scale. The answer obtained is 75 working days. On this basis we determine the beginning date for each activity (for instance, the F activity starts in the 27-Th day of the project).We can pass afterwards at the establishment of the starting moment, taking

into account the working days in a month. We may see that the work starts on Wednesday, 1St of April and ends on Monday, 20Th of July 1998.