Chapter 7 Flashcards

1
Q

Network diagrams

A

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

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2
Q

2 construction methods of network diagrams

A
  1. AON mode (activity on mode)

2. AOA mode (activity on arrow)

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3
Q

AON mode

A
  • 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)
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4
Q

2 types of dependency relationships

A
  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)
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5
Q

creating a project network

A

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

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6
Q

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

A

the whole project is delayed

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7
Q

Early times: early start and early finish

A

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

  • ES depends on the EF of its predecessor
  • do not consider potential constraints
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8
Q

Late times: late start and late finish

A

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

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9
Q

Total slack

A

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

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10
Q

Critical path

A
  • has no or the least slack
  • the time a project takes is dependent of the critical path
  • it is the longest path
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11
Q

activities on the critical path

A

critical activities

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12
Q

free slack

A

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

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13
Q

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

A

Start second task ___ days after first task starts

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14
Q

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

A

Finish second task ___ days after first task starts

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15
Q

PDM (Precedence Diagramming Method)

A

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
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16
Q

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

A

_______ day lag between predecessor and successor

Start second task ___ days after first task finishes

17
Q

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

A

finish second task ___ days after first task finishes

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

18
Q

Time Constrained Project

A
  • 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
19
Q

Resource Constrained Project

A
  • 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.
20
Q

Resource allocation

A

assigning resources to activity

21
Q

Workload (and formula)

A

amount of work imposed on resource

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

22
Q

Resource Loading

A

amount of particular resource needed to conduct all allocated activities

23
Q

Loading for particular resources depends of

A
  1. amount of resource needed by project activities

2. start and finish dates of those activities

24
Q

Resource levelling

A

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

25
Downside to splitting activities into pieces and schedule them at different times
can lead to wasted time and longer activity duration
26
Laddering
continue to the next component before entire design is complete
27
Managing multi-project resource schedules
- 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
28
Problems with multi-project resource schedules
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
29
Criticism of network methods
- 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
30
Variability of Activity Duration
- Activity duration is not a single, deterministic value | - there is a range of possible durations for most activities
31
Sensitivity of a network
the likelihood that the original critical path(s) will change once the project is initiated
32
the sensitivity of a network is the function of
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
33
advantage of networks
they clearly display the interdependencies of project activities and show the scheduling impact that activities have on each other