Large Scale Systems Design G52LSS

Transcription

1 LSS antt harts Lecture 8 antt harts and PM onstructing antt harts Staff Profile and Utilisation Learning outcomes: interpret the information in antt charts; construct antt charts following Pert/PM method; determine staff profile and staff utilisation for a project following the antt chart and staff requirements. 1

2 antt harts project schedule represents the sequencing of the project activities and milestones in a clear and logical manner to facilitate project execution and control. fter the PRT/PM analysis is completed, the following phase is to construct the NTT chart and then to re-allocate resources and re-schedule if necessary. NTT chart is a useful graphical tool to aid project management. In a antt chart tasks are represented as horizontal bars.

3 haracteristics of antt harts The bar in each row identifies the corresponding task The horizontal position of the bar identifies start and end times of the task ar length represents the duration of the task Offer simple and good visual communication Task durations can be compared easily ood for allocating resources and re-scheduling Precedence relationships is represented using arrows ritical activities are usually highlighted Slack times are represented using bars with doted lines Milestones can be represented by special shapes Minor changes in data can cause major changes in the chart

4 arly start NTT chart the bar of each activity begins at the activity earliest start time (S)

5 Late start NTT chart the bar of each activity ends at the activity latest finish time (L)

6 onstructing antt harts The steps to construct an early antt chart using the information obtained from the PRT/PM analysis are as follows: 1. Schedule the critical tasks in the correct position. Place the time windows in which the non-critical tasks can be scheduled (S and L). Schedule the non-critical tasks according to their earliest starting (S) times. Indicate precedence relationships between tasks Note: to construct a late antt chart use the latest starting (LS) time to schedule non-critical tasks.

7 xample 8.1 onstruct an early antt chart for the following project. () / () 11/11 () / (7) 1/1 () / () /1 () Task Precedence, uration 7 S LS L Slack 7

8 xample 8.1 (cont.) Step

9 xample 8.1 (cont.) Step

10 xample 8.1 (cont.) Step

11 xample 8.1 (cont.) Step

12 xample 8. onstruct a late antt chart for the following project. / () / / 8 () / 1 1 / 1 () 1 / 1 1 / 17 () 1 / 19 / Start / 19 / H() 19 / / 7 I() / 7 7 / 7 nd 7 / 7 / 1 (1) / 1 1 / 17 (7) 1 / / 19 () 17 / 19 1

13 xample 8. (cont.) Step 1 Step Step Step H I

14 Staff Profile and Utilisation The staff profile, showing the overall staff needs during the project, can be obtained with the project schedule (antt chart) and the staff requirements of each task. Staff utilisation gives an indication of how the average efficiency in which the available staff hours are being utilised during the project. Resource smoothing if often used to re-allocate resources and re-schedule activities when staff (or other resources) is not available at the required level. The non-critical tasks are re-scheduled within their time window avoiding as much overlap as possible. 1

15 The staff profile is a graph that gives the total required staff at every time in the project. The staff utilisation is calculated by dividing the area of staff requirements by the area inside the staff profile envelope. Staff tisi i 1 Utilisation max s i L l 1 L i l where n is the number of activities t i s i i is is the duration of the staff is the set of L is the duration of n activity i requirements of activities being executed at time l the project activity i 1

16 xample 8. Obtain the staff profile and staff utilisation for the following project. 7 Task uration 7 Required Staff

17 xample 8. (cont.) Staff utilisation % 7 Task uration 7 Required Staff

18 xercise 8.1 onstruct the early antt, staff profile and calculate staff utilisation for the following project. Task H I Precedence,,, uration Staff 8 S LS L Slack 1 1 / (8) 8/1 () (7) (8) / 1/1 (8) 1/1 I(7) 8/8 () / () 1/1 H() 18

19 xercise 8.1 (cont.) The early antt chart H I

20 xercise 8.1 (cont.) The staff profile and utilisation Staff utilisation.7 7.%

21 dditional Reading hapter of (Maylor, ) hapter of (Kendall and Kendall, ) 1