SEG7490 Project and Technology Management

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SEG7490 Project and Technology Management

• Part I Project Management
• Overview.
• Project screening and selection.
• Multiple-criteria methods for evaluation.
• Project structuring
• Project scheduling
• Budgeting and resource management.
• Life-cycle costing.
• Project control.
• Computer support for project management.
• Part II Technology Management
• Strategic and operational considerations of
  technology
• Forecasting of technology
• Management of RD projects

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Chapter 5. Project Scheduling

• 5.1 Introduction
• 5.2 Estimation of the duration of project
  activities
• 5.3 CPM analysis The activity-on-arrow
  network
• 5.4 CPM analysis The activity-on-node
  network
• 5.5 CPM analysis The linear programming
  approach
• 5.6 The PERT approach

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5.1 Introduction

• Project Scheduling is to determine the schedules
  to perform the various activities (tasks)
  required to complete the project, subject to all
  constraints such as the technological limits on
  the activities of the project, the availability
  of resources and budget, and the due date
  requirements.

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5.1 Introduction

• Project scheduling aims to obtain answers to the
  following questions
• (1) If each of the activities goes according to
  plan, when will the
• project be completed ?
• (2) Which tasks are most critical to ensure the
  timely completion
• of the project ?
• (3) Which tasks can be delayed, if necessary,
  without delaying
• project completion, and by how much ?
• (4) Specifically, at what times should each
  activity begin and end ?
• (5) At any given time during the project, what is
  the range of
• dollars that should be spent ?
• (6) Is it worthwhile to incur extra costs to
  accelerate some of the
• activities ?

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5.1 Introduction

• Questions 1-4 relate to time, which will be
  dealt with in this chapter. Questions 5-6 relate
  to the possibility of trading off between time
  and money, which will be discussed in next
  chapter.

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5.1 Introduction

• Main approaches used for project scheduling
• CPM (critical path method)
• PERT (program evaluation and review technique)
• CPM assumes that activity times are
  deterministic, while PERT views the time to
  complete a task as a random variable.
• Both approaches work on a project network, which
  graphically portrays the activities of the
  project and their relationships.

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5.1 Introduction

• To use either CPM or PERT for project
  scheduling, we need to first perform
• Estimation of activity duration
• Development of the project to represent the
  relationships between all activities.

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5.2 Estimation of the duration of project
activities

• Two approaches
• (1) The deterministic approach, which ignores
  uncertainty thus results in a point estimate
  (e.g. The duration of task 1 23 hours, etc.)
• (2) The stochastic approach, which considers the
  uncertain nature of project activities by
  estimating the expected duration of each activity
  and its corresponding variance.
• The stochastic approach To analyse the past
  data to construct the probabilistic distribution
  of a task.

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5.2 Estimation of the duration of project
activities

• Example An activity was performed 40 times in
  the past, requiring a time between 10 to 70
  hours. The figure below shows the frequency
  distribution.

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5.2 Estimation of the duration of project
activities

• The probability distribution of the activity is
  approximated by the frequency distribution.

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5.2 Estimation of the duration of project
activities

• In project scheduling, we usually use a beta
  distribution to represent the time needed for
  each activity.

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5.2 Estimation of the duration of project
activities

• Three key values we use in the time estimate for
  each activity
• a optimistic time, which means that there is
  little chance
• that the activity can be completed
  before this time
• m most likely time, which will be required if
  the execution
• is normal
• b pessimistic time, which means that there is
  little chance
• that the activity will take longer.

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5.2 Estimation of the duration of project
activities

• The expected or mean time is given by
• D (a4mb)/6
• The variance is
• V2 (b-a) 2/36
• For Figure 7-3, we have a10, b70, m35.
• Therefore D36.6, and V2 100.

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5.3 CPM analysis The activity-on-arrow network

• A network approach, to model the activities and
  their precedence relationships, and to perform
  scheduling analysis based on the network.

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5.3.1 Project network construction

• A project network is created, where
• An arc represents an activity of the project
• A node represents an event that signifies the
  completion of an activity or the beginning of a
  new activity.

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5.3.1 Project network construction

• Examples
• Figure 7-14a represents the activity (i, j).
• Figure 7-14b represents three activities (1,3),
  (2,3), and (3,4). It also indicates that
  activity (3,4) cannot begin until activities
  (1,3) and (2,3) have been completed.

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Rules to construct the project network

• Rule 1. Each activity is represented by one and
  only one arrow (arc) in the network.
• Rule 2. No two activities can be identified by
  the same head and tail events.

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Rules to construct the project network

• Example In Figure 7-15, the activities A and B
  run in parallel, which would all be identified by
  activity (1,3) if we simply use the network in
  7-15a. To get around this problem, we use dummy
  activity. See Figure 7-15b.

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Rules to construct the project network

• Dummy activity A dummy activity is not a real
  activity. It does not consume time or resources.
  
• Dummy activities are very useful, which can also
  be used to establish the logical relationships
  that cannot otherwise be represented correctly.

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Rules to construct the project network

• Example Suppose in a project, activities A and
  B must precede C, while activity E must be
  preceded only by B. Figure 7-16a is not correct.
  The correct representation should be using a
  dummy activity D1 as in Figure 7-16b.

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Rules to construct the project network

• Rule 3. To ensure the correct representation in
  the project network, the following questions must
  be answered as each activity is added to the
  network
• Which activities must be completed immediately
  before this activity can start ?
• Which activities must immediately follow this
  activity?
• Which activities must occur concurrently with
  this activity ?

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Rules to construct the project network

• Rule 4. All activities that have no predecessors
  should be connected to a common start node, while
  all activities that have no successors should
  have a common end node.
• Rule 5. The nodes should be so numbered that,
  for each activity (i, j), i

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Rules to construct the project network

• Example

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Rules to construct the project network

• The process begins by identifying all activities
  that have no predecessors and joining them to a
  unique start node

• Since activity C has only one predecessor A, it
  can
• be added immediately to the network.

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Rules to construct the project network

• Activity D has both A and B as predecessors thus
  there is a need for an event that represents the
  completion of A and B. We add two dummy
  activities D1 and D2

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Rules to construct the project network

• Before starting activity F, activities C, E, and
  D must be completed. Therefore, an event should
  be introduced to represent the terminal point of
  these activities

• Activity G has only F as its predecessor and
  thus can start
• from the head of F.

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Rules to construct the project network

• Once all the activities and their precedence
  relations have been included in the network, we
  can check to eliminate redundant dummy
  activities.
• A dummy activity is redundant if it is the only
  activity starting or ending at a given event.
• For the example, we can find that D2 is redundant
  and can be eliminated as shown below.

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Rules to construct the project network
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Rules to construct the project network

• Example Construct an AOA network for a project
  with activities A,B,C,, L, which have the
  following relationships
• A, B, and C, the first activities of the project
  that can start simultaneously.
• A and B precede D.
• B precedes E, F, and H.
• F and C precede G.
• E and H precede I and J.
• C, D, F, and J precede K.
• K precedes L.
• I, G, and L are the terminal activities of the
  project.

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Rules to construct the project network
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Rules to construct the project network

• In general, once the nodes in a network are
  numbered, the network can be represented by a
  matrix whose respective rows and columns
  correspond to the start and end events of a
  particular activity. The matrix for the example
  of Fig 7-22 is as follows