Chapter 6. Terminology AOA and AON diagrams Determining Project Duration, Critical Path Special

Chapter 6

• Terminology• AOA and AON diagrams• Determining Project Duration, Critical Path• Special

• Activity: an element of the project that requires time.

• Merge Activity: an activity that has two or more preceding activities on which it depends.

• Parallel (Concurrent) Activities: Activities that can occur independently and, if desired, not at the same time.

A

C

B D

• Path: a sequence of connected, dependent activities.

• Critical path: the longest path through the activity network that allows for the completion of all project-related activities;

C

A B D

• Slack (or Float)– The amount of time an activity can be delayed

after the start of a longer parallel activity or activities.

• Total slack– The amount of time an activity can be delayed

without delaying the entire project.

Activity Activity RelationshipsRelationships

Activity RelationshipActivity Relationship

AOA AON


S precedes T, which precedes U.S precedes T, which precedes U.

AOA AON

1 2S

3T

4U

S T U


S and T must be completed before U can be started.S and T must be completed before U can be started.

AOA AON

S

T

U

1

2

3T

S

4U


T and U cannot begin until S has been completed.T and U cannot begin until S has been completed.

AOA AON

T

U

S

3

4

1

T

U2S


U and V cannot begin until both S and T have been completed. U and V cannot begin until both S and T have been completed.

AOA AON

1

2

4

5

U

V

S

T 3

S

T

U

V


U cannot begin until both S and T have been completed; V cannot U cannot begin until both S and T have been completed; V cannot begin until T has been completed.begin until T has been completed.

AOA AON

S

T

U

V

1 3

DummyDummy

5

2 4 6

S U

T V


T and U cannot begin until S has been completed; V cannot begin T and U cannot begin until S has been completed; V cannot begin until both T and U have been completed.until both T and U have been completed.

AOA AON

1 2 4

3

S T5

V

UDummyDummy

S T V

U

St. Adolf’s HospitalSt. Adolf’s Hospital

ImmediateImmediateActivityActivity DescriptionDescription Predecessor(s)Predecessor(s) ResponsibilityResponsibility

AASelect administrative and medical staff.Select administrative and medical staff.BBSelect site and do site survey.Select site and do site survey.CCSelect equipment.Select equipment.DDPrepare final construction plans and layout.Prepare final construction plans and layout.EEBring utilities to the site.Bring utilities to the site.FFInterview applicants and fill positions inInterview applicants and fill positions in

nursing, support staff, maintenance, nursing, support staff, maintenance, and security.and security.

GGPurchase and take delivery of equipment.Purchase and take delivery of equipment.HHConstruct the hospital.Construct the hospital.IIDevelop an information system.Develop an information system.JJInstall the equipment.Install the equipment.KKTrain nurses and support staff.Train nurses and support staff.



AASelect administrative and medical staff.Select administrative and medical staff. ——JohnsonJohnsonBBSelect site and do site survey.Select site and do site survey. —— TaylorTaylorCCSelect equipment.Select equipment. AA AdamsAdamsDDPrepare final construction plans and layout.Prepare final construction plans and layout. BB TaylorTaylorEEBring utilities to the site.Bring utilities to the site. BB BurtonBurtonFFInterview applicants and fill positions inInterview applicants and fill positions in AAJohnsonJohnson


GGPurchase and take delivery of equipment.Purchase and take delivery of equipment. CC AdamsAdamsHHConstruct the hospital.Construct the hospital. DD TaylorTaylorIIDevelop an information system.Develop an information system. AASimmonsSimmonsJJInstall the equipment.Install the equipment. E,G,HE,G,H AdamsAdamsKKTrain nurses and support staff.Train nurses and support staff. F,I,JF,I,JJohnsonJohnson






Example 8.1Example 8.1


























































































































Forward Forward Pass:Pass:Earliest Earliest StartStart&&Earliest Earliest FinishFinish

A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

I

15

F

10

FinishStart


A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

0 12

I

15

F

10

12 27

12 22 63 69

22 57

59 6319 59

9 33

0 9 9 19

12 22

Backward Backward Pass:Pass:Latest Latest StartStartandandLatest Latest Finish Finish TimesTimes

FinishStart

• Laddering– Activities are broken into segments so the

following activity can begin sooner and not delay the work.

• Lags– The minimum amount of time a dependent

activity must be delayed to begin or end.

• Hammock

Documents

Chapter 6. Terminology AOA and AON diagrams Determining Project Duration, Critical Path Special