Resource Management

Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall12-2 Types of Constraints  Time  Resource  Mixed Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

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.

Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall12-5 Resource Loading The amounts of individual resources that a schedule requires during specific time periods. Resource loading table Resource NameWorkDetails5/55/125/195/26 Tom40 hrsWork8h32h Assign Bids40 hrsWork8h32h Jeff40 hrsWork8h32h Calculate Cost40 hrsWork8h32h Sue40 hrsWork8h32h Select Bid40 hrsWork8h32h Carol8 hrsWork8h PR Campaign8 hrsWork8h

What to do with non-linear duration-resource functions? Use a computer Focus on quasi-linear parts of the functions

Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall12-7 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 Hall12-8 Prioritization Rules for Leveling  Smallest amount of slack  Smallest duration  Lowest ID number  Greatest number of successor tasks  Requiring the most resources

Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall12-9 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 Hall12-10 Creating Resource Loading Charts (1/4) Display the amount of resources required as a function of time. 0 A4 Res = 6 4 B5 Res = 2 5 D9 Res = 7 9 E11 Res = 3 4 C7 Res = 2 11 F12 Res = 6 1.Start with a network diagram

Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall12-11 Creating Resource Loading Charts 2/4 ActivityResourceDurationESSlackLF A64004 B21405 C D74509 E3290 F 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 Hall12-12 Creating Resource Loading Charts 3/4 A C B D E F Project Days Resources 3.Draw an initial loading chart with each activity scheduled at its ES. Resource imbalance

Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall12-13 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. A C B D E F Project Days Resources C

Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall12-14 Key Parameters in Multi-Project Environments  Schedule slippage  Resource utilization  In-process inventory

Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall12-15 Prioritizing Resource Allocations in Multi-Project Environments First come first served Greatest resource demand Greatest resource utilization Minimum late finish time Mathematical programming

Problem solving

Network with single resource data START (0) e (1) d (2) c (3) b (4) a (1) FINISH (0)

Aggregation with a bar chart (single resource, earliest start) activity a11 b44444 c d22222 e111 Res. aggr Cum. res Resource units Time

Aggregation with a bar chart (single resource, latest start) activity a11 b44444 c d22222 e111 Res. aggr Cum. res Resource units Time

The S Curve analysis The minimum slope level is the less ‘critical’ from the viewpoint of availability

S Curve of the example

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 Time Trying to keep the original TPT unchanged means that critical activities should not be moved. Thus try to move activities with free float. Resource units Time

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 Time

activity a11 b44444 c d e111 Res. aggr Cum. res Solution

S Curve

Effect of levelling New „activity”: waiting for the resource (it is a lag, not a true activity) START (0) e (1) d (2) c (3) b (4) a (1) FINISH (0) Changes: new precedence relationship, floats, late start and finish times

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 Hall12-28