Question

EX8-4 (Algo) You have prepared the following schedule... You have prepared the following schedule for a project in which the key resource is a tractor. There are three tractors available to the project. The resource requirements are as shown in the diagrams below. Develop a resource-constrained schedule. Use the parallel method and heuristics given. Be sure to update each period as the computer would do. Legend ESIDER SUK RES SUK U DURU 106 12 OO 5510 0155 5 5

Answer 1

Gantt chart and Resource loading chart based on Earliest Start time is following:

ID 3 4 Gantt chart based on earliest start time RES DURE LS EF LF Slack 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1 4 0 1 4 5 1 2 500 550 2 4 4 6 8 10 2 1 5 5 5 10 100 2 3 5 7 8 10 2 | 3 2 10 10 12 12 0 Resources scheduled 3 3 3 3 4 5 5 5 11 33 000 Resources available Resource Loading Chart Resources Scheduled 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Duration 11 12 13 14 15 16

In the resource loading diagram, we see that resource usage in TP 5,6,7,8 exceeds the available resources, which is 3 .

The resource over-allocation is because of parallel occurrence of tasks 3,4 and 5

Tasks 3 and 5 have slack of 2 TPs. each. So tasks 3 and 5 have to be rescheduled.

After rescheduling tasks 3 and 5, the resulting Gantt chart and resource loading profile based on resource constraint is following:

Gantt chart based on resource-constraint ID RES DUR E LS EF LF Slack 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 140 145 1 2 2 5 0 0 5 5 0 324 55 990 4 1 5 5 7 10 12 2 52 | 3 | 9 9 12120 6 3 2 12 12 14 14 0 Resources scheduled 3 3 3 3 2 3 3 3 3 3 2 2 3 3 0 Resources available 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 Resource Loading Chart Resources Scheduled 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Duration 11 12 13 14 15 16

If NOT resource-constrained, project will take : 12 time periods

Resources-constrained project will take :   14 time periods

Order in which activities are scheduled are:

First	2
Second	1
Third	3
Fourth	4
Fifth	5
Sixth	6