Resource Management Types of Constraints Time Resource Mixed Copyright 2010 Pearson Education, Inc. Publishing as Prentice Hall 12-2 Resources Definition: anything that is scarce and required for any activity in the project. Resources are constraints for the project. Resources can be: Non-storable: has to be renewed for each period e.g. work Storable: depleted only by usage (remains available if not used) e.g. money The most common resource typology, the 4Ms: Men Machines Money (cost) Material Other Loading (resource allocation) The assignment of work to an worker, machine or unit (generally: to a workstation) in time. A workstation can be: underloaded (load < capacity) fully loaded (load = capacity) overloaded (load > capacity) Fully loading is nearly impossible to reach except in flow production. Underloading is the most common, because it respects time. Overloading leads to be late. Resource Loading The amounts of individual resources that a schedule requires during
specific time periods. Resource loading table Resource Name Work Details 5/5 5/12 5/19 5/26 Tom 40 hrs Work 8h 32h Assign Bids 40 hrs Work 8h 32h 40 hrs Work 8h 32h Calculate Cost 40 hrs Work 8h 32h 40 hrs Work 8h 32h
Select Bid 40 hrs Work 8h 32h Jeff Sue Carol 8 hrs Work 8h PR Campaign 8 hrs Work 8h Copyright 2010 Pearson Education, Inc. Publishing as Prentice Hall 12-5 What to do with non-linear durationresource functions? Use a computer Focus on quasi-linear parts of the functions Resource Leveling (Smoothing) A multivariate, combinatorial problem Objectives To determine the resource requirements so that they will be available at the right time To allow each activity to be scheduled with the smoothest possible transition across resource usage levels Copyright 2010 Pearson Education, Inc. Publishing as Prentice Hall 12-7 Prioritization Rules for Leveling Smallest amount of slack Smallest duration
Lowest ID number Greatest number of successor Requiring the most tasks resources Copyright 2010 Pearson Education, Inc. Publishing as Prentice Hall 12-8 General Procedure for Leveling 1. Create a project activity precedence table and network diagram, 2. Develop resource loading tables and a resource profile 3. Determine activity late finish times 4. Identify resource over allocation 5. Level the resource loading table 6. Recalculate net activity slacks and project delay Copyright 2010 Pearson Education, Inc. Publishing as Prentice Hall 12-9 Creating Resource Loading Charts (1/4) Display the amount of resources required as a function of time. 4 B 5 Res = 2
0 A 4 Res = 6 5 D 9 Res = 7 9 E 11 Res = 3 1. Start with a network diagram 4 C 7 Res = 2 Copyright 2010 Pearson Education, Inc. Publishing as Prentice Hall 11 F 12 Res = 6 12-10 Creating Resource Loading Charts 2/4 Activity Resource Duration ES Slack LF A 6 4 0 0 4 B 2 1 4
0 5 C 2 3 4 4 11 D 7 4 5 0 9 E 3 2 9 0 11 F 6 1 11
0 12 2. Produce a table that shows the duration, early start, late finish, slack, and resource(s) required for each activity. Copyright 2010 Pearson Education, Inc. Publishing as Prentice Hall 12-11 Creating Resource Loading Charts 3/4 3. Draw an initial loading chart with each activity scheduled at its ES. Resources 8 6 4 A D B 2 C 2 4 F Resource imbalance E 6 8 10 12 Project Days Copyright 2010 Pearson Education, Inc. Publishing as Prentice Hall 14 12-12 Creating Resource Loading Charts 4/4
4. Rearrange activities within their slack to create a more level profile. Splitting C creates a more level project. Resources 8 6 4 A B 2 C 2 4 D C F E 6 8 10 12 Project Days Copyright 2010 Pearson Education, Inc. Publishing as Prentice Hall 14 12-13 Key Parameters in Multi-Project Environments Schedule slippage Resource utilization In-process inventory Copyright 2010 Pearson Education, Inc. Publishing as Prentice Hall 12-14 Prioritizing Resource Allocations in Multi-Project Environments
First come first served Greatest resource demand Greatest resource utilization Minimum late finish time Mathematical programming Copyright 2010 Pearson Education, Inc. Publishing as Prentice Hall 12-15 Problem solving Network with single resource data 0 2 0 0 0 0 0 0 0 0 2 a (1) 2
2 0 0 5 5 5 b (4) 5 10 c (3) 8 10 3 5 0 10 0 2 START (0) 0 2 0 5 3
7 d (2) 5 10 10 10 0 13 e (1) 3 13 0 13 0 13 FINISH (0) 13 0 13 Aggregation with a bar chart (single resource, earliest start) activity 1 2
3 4 5 a 1 1 b 4 4 6 7 8 9 10 4 4 4 c 3 3 3 3 3 3 3
3 d 2 2 2 2 2 e 11 12 13 1 1 1 Res. aggr. 5 5 9 9 9 5 5 3 3
3 1 1 1 Cum. res. 5 10 19 28 37 42 47 50 53 56 57 58 59 1 2 3 4 5 6 7
8 9 10 11 12 13 Resource units 11 10 9 8 7 6 5 4 3 2 1 Time Aggregation with a bar chart (single resource, latest start) activity a 1 2 1 1 3 4 5 b c
3 3 3 d 6 7 8 9 10 4 4 4 4 4 3 3 3 3 3 2 2 2 2 2
e 11 12 13 1 1 1 Res. aggr. 1 1 3 3 3 9 9 9 9 9 1 1 1 Cum. res. 1 2 5
8 11 20 29 38 47 56 57 58 59 1 2 3 4 5 6 7 8 9 10 11 12 13 Resource units 11
10 9 8 7 6 5 4 3 2 1 Time The S Curve analysis The minimum slope level is the less critical from the viewpoint of availability S Curve of the example 70 60 50 40 ES LS 30 smoothest 20 10 0 1 2 3 4 5 6 7 8
9 10 11 12 13 Other possibilities Alternative resources Alternative methods Alternative sequences (if there is no technical dependency) Levelling the load We must have a starting allocation of activities over time and a resource constraint (previous example). Resource units 11 10 9 8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8 9
10 11 12 Time Trying to keep the original TPT unchanged means that critical activities should not be moved. Thus try to move activities with free float. 13 Solution There are only 2 activities with free float: b & d Which one to move and to where? Moving activity d 3 days in advance is eliminating the peak. Resource units 11 10 9 8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 Time
8 9 10 11 12 13 Solution activity 1 2 3 4 5 a 1 1 b 4 4 6 7 8 9 10 4
4 4 c 3 3 3 3 3 3 3 3 d - - - 2 2 2 2 2 e 11 12 13
1 1 1 Res. aggr. 5 5 7 7 7 5 5 5 5 5 1 1 1 Cum. res. 5 10 17 24 31 36 41
46 51 56 57 58 59 S Curve 70 60 50 ES 40 LS smoothest 30 leveled 20 10 0 1 2 3 4 5 6 7 8 9
10 11 12 13 Effect of levelling New activity: waiting for the resource (it is a lag, not a true activity) 0 2 0 0 0 0 0 0 0 0 2 a (1) 2 2 0 0 0 0 5 b
(4) 5 5 c (3) 8 10 0 0 0 10 0 5 START (0) 0 2 0 5 0 10 d (2) 5 10 10 10
0 13 e (1) 3 13 0 13 0 13 FINISH (0) 13 Changes: new precedence relationship, floats, late start and finish times 0 13 Optional homework Hypothetical project resource analysis and planning (4*5pts): Resource need per activity Loading chart Network diagram Smoothing with resource loading charts Copyright 2010 Pearson Education, Inc. Publishing as Prentice Hall 12-28
