Chapter 12Chapter 12

Network Network SchedulingSchedulingTechniquesTechniques

Scheduling Scheduling TechniquesTechniques

• Gantt or bar chartsGantt or bar charts

• Milestone chartsMilestone charts

• Line BalancingLine Balancing

• NetworksNetworks– Program Evaluation and Review Technique (PERT)Program Evaluation and Review Technique (PERT)– Arrow Diagram Method (ADM) also called the Arrow Diagram Method (ADM) also called the

Critical Path Method (CPM)Critical Path Method (CPM)– Graphical Evaluation and Review Technique Graphical Evaluation and Review Technique

(GERT)(GERT)– Precedence Diagram Method (PDM)Precedence Diagram Method (PDM)

Scheduling AdvantagesScheduling Advantages

• Needed for planningNeeded for planning

• Evaluate alternatives (what-if’s)Evaluate alternatives (what-if’s)

• Resource schedulingResource scheduling

• ControllingControlling

Bar (Gantt) ChartsBar (Gantt) Charts

TASKS 1 2 3 4 5

4

MONTHS AFTER GO-AHEAD

3

2

1

5

Milestone Milestone ChartChart

ACTIVITY

TESTINGANALYSISREPORTPRESENTATION

TIME

Standard PERT Standard PERT NomenclatureNomenclature

6 3

COMPLETE TESTING COMPLETE FINAL REPORT

3 WEEKS

LEGENDLEGEND

EVENT

ACTIVITY

DependencieDependenciess

7

26 18

31

7

18

31

26

BURST POINT SINK

Simplified PERT Simplified PERT NetworkNetwork

1 9

3

4

2 8765

LEGEND: (TIME = WEEKS)

EVENTACTIVITYCRITICAL PATH ACTIVITY

Dummy Dummy ActivitiesActivities

A

B

C

D

DUMMY

ACTIVITYPRECEDING

ACTIVITYA - B - C B D A,B

NETWORK FOR HOUSE NETWORK FOR HOUSE CONSTRUCTIONCONSTRUCTION

1 2 3 4

67

8

15 17

185

14

13

9

10

11

12

EXC &POUR FOOTINGS

POURFOUND.

ERECTFRAME & ROOF

LAYBRICKWORK

INSTALLDRAINS

POURBASEMENTFLOOR

INSTALL COOLING & HEATING

INSTALL ROUGHELECT. & PLUMB

LAYSTORM DRAINS

FINISHROOF

FINISH GRADING

POUR WALKS &LANDSCAPE

FINISHFLOORS

FINISH ELECTR.WORK

FINISHCARPETING

PAINT

INSTALLKITCHEN EQUIP.

INSTALLFIN. PLUMB

INSTALLDRY WALL

16

INSTALL ROOFDRAINAGE

LAYFLOORING

Slack Slack IdentificationIdentification

C (8,10)

2 (15,17)

EARLIEST START TIME

EARLIEST FINISH TIME

LATEST FINISH TIME

LATEST START TIME

ACTIVITY

TIME

Schedule Schedule CompressionCompression• Elimination of some parts of the project Elimination of some parts of the project

• Addition of more resourcesAddition of more resources

• Substitution of less time-consuming Substitution of less time-consuming components or activitiescomponents or activities

• Parallelization of activitiesParallelization of activities

• Shortening critical path activitiesShortening critical path activities

• Shortening early activitiesShortening early activities

• Shortening longest activitiesShortening longest activities

Schedule Schedule Compression Compression (Continued)(Continued)

• Shortening easiest activitiesShortening easiest activities

• Shortening activities that are least Shortening activities that are least costly to speed upcostly to speed up

• Shortening activities for which you Shortening activities for which you have more resourceshave more resources

• Increasing the number of work hours Increasing the number of work hours per day per day

Resource LevelingResource Leveling• Resource leveling is an attempt to Resource leveling is an attempt to

eliminate the manpower peaks and eliminate the manpower peaks and valleys by smoothing out the period-to-valleys by smoothing out the period-to-period resource requirements. The period resource requirements. The ideal situation is to do this without ideal situation is to do this without changing the end date. However, in changing the end date. However, in reality, the end date moves out and reality, the end date moves out and additional costs are incurred.additional costs are incurred.

Resource AllocationResource Allocation• Resource allocation (or resource Resource allocation (or resource

limited planning) is an attempt to find limited planning) is an attempt to find the shortest possible critical path the shortest possible critical path based upon the available or fixed based upon the available or fixed resources. The problem with this resources. The problem with this approach is that the employees may approach is that the employees may not be qualified technically to perform not be qualified technically to perform work on more than one activity in a work on more than one activity in a network.network.

Types Of Precedence Types Of Precedence ChartsCharts

ACTIVITY 1

ACTIVITY 1

ACTIVITY 2

ACTIVITY 2FINISH-TO-START

START-TO-START

FINISH START

START

START

Types Of Precedence Types Of Precedence ChartsCharts

ACTIVITY 1

ACTIVITY 1

ACTIVITY 2

ACTIVITY 2

FINISH-TO-FINISH

PERCENT COMPLETE

FINISHFINISH

20 %

50 %