Chapter 7

Question 1

Network diagrams

Answer 1

shows project activities or tasks and their logical relationships
also shows events (instants in time; start of an activity)

Question 2

2 construction methods of network diagrams

Answer 2

1. AON mode (activity on mode)

2. AOA mode (activity on arrow)

Question 3

AON mode

Answer 3

• each activity (work package or task) in project is represented by a node
• project represented as arrows and nodes (arranged in sequence as specified by immediate predecessors)

Question 4

2 types of dependency relationships

Answer 4

1. mandatory
   - sequence of 2 actions can’t be reversed
   - dependency can’t be eliminated
2. discretionary
   - sequence is a matter of choice
   - dependency can be eliminated (and activities overlapped to speed up process = fast tracking)

Question 5

creating a project network

Answer 5

created using list of activities from Work Breakdown Structure and their predecessors

Question 6

What happens when a delay occurs in one of the activities on the critical path?

Answer 6

the whole project is delayed

Question 7

Early times: early start and early finish

Answer 7

earliest that activities can be started (ES) and finished (EF)

• ES depends on the EF of its predecessor
• do not consider potential constraints

Question 8

Late times: late start and late finish

Answer 8

latest allowable times an activity can start (LS) and finish (LF) without delaying project completion
- LF depends on the LS for its successor

Question 9

Total slack

Answer 9

amount of allowable deviation between the latest an activity must take place and the earliest it can take place
–> how much an activity can be delayed without delaying the whole project

Question 10

Critical path

Answer 10

• has no or the least slack
• the time a project takes is dependent of the critical path
• it is the longest path

Question 11

activities on the critical path

Answer 11

critical activities

Question 12

free slack

Answer 12

the time an activity can be delayed without delaying the start of any successor activity

Question 13

Alternative precedence relationships: Start-to-start (SS)

Answer 13

Start second task ___ days after first task starts

Question 14

Alternative precedence relationships: Start-to-finish (SF)

Answer 14

Finish second task ___ days after first task starts

Question 15

PDM (Precedence Diagramming Method)

Answer 15

shows the kinds of relationships in a project

1. Start activity when predecessors are only partially completed
2. Start activity n days after start of predecessor
3. Start activity n days after predecessors are completed
4. Finish activity n days after finished predecessor

Question 16

Alternative precedence relationships: Finish-to-start (FS)

Answer 16

_______ day lag between predecessor and successor

Start second task ___ days after first task finishes

Question 17

Alternative precedence relationships: Finish-to-finish (FF)

Answer 17

finish second task ___ days after first task finishes

–> mostly used with zero lag where activities must end on the same day

Question 18

Time Constrained Project

Answer 18

• A project that must be completed by an
  imposed date
• Time is fixed, resources are flexible
  –> sometimes resources are required to ensure project meets schedule

Question 19

Resource Constrained Project

Answer 19

• A project in which the level of resources available cannot be exceeded
• Resources are fixed, time is flexible
• -> inadequate resources will delay the project
• Resource levelling (or smoothing) involves attempting to even out demands on resources by using slack (delaying non critical activities) to manage resource utilisation.

Question 20

Resource allocation

Answer 20

assigning resources to activity

Question 21

Workload (and formula)

Answer 21

amount of work imposed on resource

working days/year) x (productive working hours/day

Question 22

Resource Loading

Answer 22

amount of particular resource needed to conduct all allocated activities

Question 23

Loading for particular resources depends of

Answer 23

1. amount of resource needed by project activities

2. start and finish dates of those activities

Question 24

Resource levelling

Answer 24

alter schedules of project activities such that the resultant workload for a required resource is somewhat uniform throughout the project
–> do this by adding slack

Question 25

Downside to splitting activities into pieces and schedule them at different times

Answer 25

can lead to wasted time and longer activity duration

Question 26

Laddering

Answer 26

continue to the next component before entire design is complete

Question 27

Managing multi-project resource schedules

Answer 27

• create project offices or departments to oversee the scheduling of resources across projects
• Use a project priority queuing system: first come, first served for resources
• centralise project management: treat all projects as a part of a “mega project”
• apply Critical Chain Methods to all project scheduling
• outsource projects/project sections to reduce the number of projects handled internally

Question 28

Problems with multi-project resource schedules

Answer 28

1. Overall project slippage
   - delay on one project creates delays for other projects
2. inefficient resource application
   - the peaks and valleys of resource demands create scheduling problems and delays for projects
3. resource bottlenecks
   - shortages of critical resources required for multiple projects cause delays and schedule extensions

Question 29

Criticism of network methods

Answer 29

• they incorporate assumptions and yield results that are sometimes unrealistic
• activities and duration require periodic modification
• failing of networks are actually inadequacies in project definition

Question 30

Variability of Activity Duration

Answer 30

• Activity duration is not a single, deterministic value

- there is a range of possible durations for most activities

Question 31

Sensitivity of a network

Answer 31

the likelihood that the original critical path(s) will change once the project is initiated

Question 32

the sensitivity of a network is the function of

Answer 32

1. the number of critical paths
2. amount of slack across near critical paths
3. the uncertainty of the time duration of activities, on and along the critical path

Question 33

advantage of networks

Answer 33

they clearly display the interdependencies of project activities and show the scheduling impact that activities have on each other