SlideShare a Scribd company logo
UNIT 2-NETWORK
OPTIMISATION
PROJECT MANAGEMENT
APPLICATIONS
• What is a project?
• Any unique endeavor with specific objectives
• With multiple activities
• With defined precedent relationships
• With a specific time period for completion
• Phases:Planning,scheduling and controlling
• Examples?
• A major event like a wedding
• Any construction project
• Designing a political campaign
PROJECT LIFE CYCLE
• Conception: identify the need
• Feasibility analysis or study: costs benefits, and risks
• Planning: who, how long, what to do?, objective and assumptions,
listing the tasks, cost/time estimation
• Scheduling: laying the activity according to precedence
Start and end time for each activity, critical path, floats and slacks
• Controlling: periodical progress reports, review
• Execution: doing the project
• Termination: ending the project
NETWORK PLANNING
TECHNIQUES
• A network is a graphic representation of a project’s operations and a
composed of activities and events that must be completed to reach the end
objective of a project, showing the planning sequence of time accomplishment,
their dependence and inter-relationship
• Program Evaluation & Review Technique (PERT):
• Developed to manage the Polaris missile project
• Many tasks pushed the boundaries of science & engineering (tasks’
duration = probabilistic)
• Critical Path Method (CPM):
• Developed to coordinate maintenance projects in the chemical industry
• A complex undertaking, but individual tasks are routine (tasks’ duration
= deterministic)
• The basic components of a network are
• Activity- An activity is a task, or item of work to be done, that
consume time, effort, money or other resources. An activity is
represented by an arrow with its head indicating the sequence
in which the events are to occur.
• Event- An event represents the start (beginning) or
completion (end) of some activity and as such it consume no
time. It has no time duration and does not consume any
resources. It is also known as a node. An event is generally
represented on the network by a circle.
• The activity can be further classified into the following three categories
• 1. Predecessor activity- An activity which must be completed before one or more other
activities start is known as predecessor activity
• 2. Successor activity- An activity which started immediately after one or more of other
activities are completed is known as successor activity.
• 3. Dummy activity- An activity which does not consume either any resource or time is
known as dummy activity. A dummy activity is depicted by dotted line in the network
diagram
• The dummy activity is inserted in the network to clarify the activity pattern in the
following two situations
To make activities with common starting and finishing points distinguishable
To identify and maintain the proper precedence relationship between activities that is
not connected by events.
For example, consider a situation where A and B are concurrent activities. C is dependent
on A and D is dependent on A and B both. Such a situation can be handled by using a
dummy activity as shown in the figure.
1
2
3
4
• The events are classified in to three categories
• 1. Merge event – When more than one activity comes and joins
an event such an event is known as merge event.
• 2. Burst event – When more than one activity leaves an event
such an event is known as burst event.
• 3. Merge and Burst event – An activity may be merge and
burst event at the same time as with respect to some activities
it can be a merge event and with respect to some other
activities it may be a burst event.
• Logical sequences in Network diagram:
• All the projects consist of certain activities that can begin only
after certain others are completed.
• In logical sequencing, following two types of errors are most
common while drawing a network diagram.
• 1. Looping: No Activity should start and end on same event.
• 2. Dangling- No activity should end without being joined to
the end event. If it is not so, a dummy activity is introduced in
order to maintain the continuity of the system. Such end event
other than the end of the project as a whole are called
dangling events.
• Rules for Network Representation
• Three rules are available for constructing the network
• 1. Each activity is represented by one, and only one arrow (arc)
• 2. Each activity must be identified by two distinct end nodes & no two or more activities can have the same
tail.
• 3. To maintain the correct precedence relationships, the following questions must be answered as each is
added to network:
• (a) What activities must immediately precede the current activity?
• (b) What activities must follow the current activity? (
• c) What activities must occur concurrently with the current activity?
• The answer of these questions may require the use of dummy activities to ensure correct precedences
among the activities.
• Numbering the events
• (a) Event numbers should be unique
• (b) Event numbering should be carried out on a sequential basis from left to right
• (c) The initial event which has all outgoing arrows with no incoming arrow is numbered 0 or 1
• (d) The head of an arrow should always bear a number higher than the one assigned at the tail of the arrow
• Example 1:Costruct the network diagram for the project with
the following activities
Activities A B C D E F G
Predecessor - - - A B C D
BOTH PERT AND CPM
• Graphically display the precedence
relationships & sequence of activities
• Estimate the project’s duration
• Identify critical activities that cannot be
delayed without delaying the project
• Estimate the amount of slack associated with
non-critical activities
• The major differences between PERT and CPM are summarized as given below
• PERT
• Event oriented
• Probabilistic in nature
• Concerned with time
• Used for new projects
• CPM
• Activity oriented
• Deterministic in nature
• Concerned with time and cost
• Used for repetitive projects
CRITICAL PATH METHOD IN
NETWORK ANALYSIS
• The notations used are
• (i, j) = Activity with tail event i and head event j
• Ei = Earliest occurrence time of event I
• Lj = Latest allowable occurrence time of event j
• Dij = Duration of activity (i, j)
• (Es)ij = Earliest starting time of activity (i, j)
• (Ef)ij = Earliest finishing time of activity (i, j)
• (Ls)ij = Latest starting time of activity (i, j)
• (Lf)ij = Latest finishing time of activity (i, j)
• Forward Pass computation
• Step 1 :The computation begins from the start node and move
towards the end node. Set E1 = 0 to indicate that the project
starts at time 0
• Step 2
• i. Earliest starting time of activity (i, j) is the earliest event
time of the tail end event i.e. (Es)ij = Ei
• ii. Earliest finish time of activity (i, j) is the earliest starting
time + the activity time i.e. (Ef)ij = (Es)ij + Dij or (Ef)ij = Ei +
Dij
• iii. Earliest event time for event j is the maximum of the
earliest finish times of all activities ending in to that event i.e.
Ej = max [(Ef)ij for all immediate predecessor of (i, j)] or Ej
=max [Ei + Dij]
• Backward Pass computation (for latest allowable time)
• Step 1 :For ending event assume E = L. (Remember that all E’s
have been computed by forward pass computations)to indicate that
the earliest and latest occurrences of the last node of the project
are the same.
• Step 2 :Latest finish time for activity (i, j) is equal to the latest
event time of event j i.e. (Lf)ij = Lj
• Step 3 :Latest starting time of activity (i, j) = the latest completion
time of (i, j) – the activity time or (Ls)ij =(Lf)ij - Dij or (Ls)ij = Lj –
Dij
• Step 4 :Latest event time for event ‘i’ is the minimum of the latest
start time of all activities originating from that event i.e. Li = min
[(Ls)ij for all immediate successor of (i, j)] = min [(Lf)ij - Dij] = min
[Lj - Dij]
DETERMINATION OF FLOATS
AND SLACK TIMES
• In case of non-critical activities, certain amount of spare time
is available and this spare time is called “float”. There are
three type of float
• Total float – The amount of time by which the completion of an
activity could be delayed beyond the earliest expected
completion time without affecting the overall project duration
time. Mathematically (Tf)ij = (Latest start – Earliest start) for
activity ( i – j)
(Tf)ij = (LFj - (ES)i-Dij or (Tf)ij = (Lj - Dij) - Ei
• Free float – The time by which the completion of an activity can be delayed
beyond the earliest finish time without affecting the earliest start of a
subsequent activity. Mathematically (Ff)ij = (Earliest time for event j –
Earliest time for event i) – Activity time for ( i, j) (Ff)ij = (Ej - Ei) - Dij
• Independent float – The amount of time by which the start of an activity can
be delayed without effecting the earliest start time of any immediately
following activities, assuming that the preceding activity has finished at its
latest finish time. Mathematically (If)ij = (Ej - Li) - Dij The negative
independent float is always taken as zero.
• Event slack - It is defined as the difference between the latest event and
earliest event times. Mathematically
Head event slack = Lj – Ej , Tail event slack = Li – Ei
Critical event – The events with zero slack times are called critical events. In
other words the event i is said to be critical if Ei = Li
Critical activity – The activities with zero total float are known as critical
activities.
Critical path – The sequence of critical activities in a network is called critical
path.
SOME NETWORK DEFINITIONS
• All activities on the critical path have zero slack
• Slack defines how long non-critical activities can be
delayed without delaying the project
• Slack = the activity’s late finish minus its early finish (or
its late start minus its early start)
• Earliest Start (ES) = the earliest finish of the
immediately preceding activity
• Earliest Finish (EF) = is the ES plus the activity time
• Latest Start (LS) and Latest Finish (LF) = the latest an
activity can start (LS) or finish (LF) without delaying
the project completion
• Ex1.A small maintenance project consist of the following jobs
whose precedence relationship is given below
Job 1-2 1-3 2-3 2-5 3-4 3-6 4-5 4-6 5-6 6-7
Duration
(days)
15 15 3 5 8 12 1 14 3 14
a)Draw an arrow diagram representing the project
b)Find the total float for each activity
c)Find the critical path and the total project duration
Early start(ES) for forward pass(incoming
arrows)
ESj=Max(ESi+Dij) value
ES1=0 0
ES2=ES1+D12 0+15 15
ES3=max(ES1+D13,ES2+D23) Max(0+15,15+3) 18
ES4=ES3+D34 18+8 26
ES5=max(ES2+D25,ES4+D45) Max(15+5,26+1) 27
Es6=max(ES3+D36,ES4+D46,ES5+D56) Max(18+12,26+14,27+3) 40
ES7=ES6+D67 40+14 54
1
2
3
4
5
6
7
A(15)
B(15
))
C(3)
D(5)
E(8)
F(12
)
G(1)
H(14
)
I(3)
J(14)
ES1=0
LC1=0
E
ES3=18
LC3=18
ES4=26
LC4=26
ES5=27
LC5=37
ES6=40
LC6=40
ES7=54
LC7=54
Latest Complete(LC) for Backward pass(Outgoing arrows) LCi=min(LCj-Dij) value
LC7=ES7 54
LC6=LC7-D67 54-14 40
LC5=LC6-D56 40-3 37
LC4=min(LC5-D45,LC6-D46)
=min(37-1,40-14)
40-14 26
LC3=min(LC4-D34,LC6-D36)
=min(26-8,40-12)
26-8 18
LC2=min(LC3-D23,LC5-D25)
=min(18-3,37-5)
18-3 15
LC1=min(LC2-D12,LC3-D13)
=min(15-15,18-15)
15-15 0
c)Critical Path conditions
1.ESi=LCi 2.ESj=LCj 3.ESj-ESi=Dij
Critical path:1-2-3-4-6-7
Project duration=15+3+8+14+14=54days
Activity Duration Total float=LCj-Dij-Esi Free Float=ESj-Dij-ESi Independent float=ESj-Dij-
LCi
1-2 15 LC2-D12-ES1=15-15-0=0 ES2-D12-Es1=15-15-0=0 ES2-D12-LC1=15-15-0=0
1-3 15 LC3-D13-ES1=18-15-0=3 ES3-D13-ES1=18-15-0=3 ES3-D13-LC1=18-15-0=3
2-3 3 LC3-D23-ES2=18-3-15=0 ES3-D23-ES2=18-3-15=0 ES3-D23-LC2=18-3-15=0
2-5 5 LC5-D25-ES2=37-5-15=17 ES5-D25-ES2=27-5-15=7 ES5-D25-LC2=27-5-15=7
3-4 8 LC4-D34-ES3=26-8-18=0 ES4-D34-ES3=26-8-18=0 ES4-D34-LC3=26-8-18=0
3-6 12 LC6-D36-ES3=40-12-18=10 ES6-D36-ES3=40-12-18=10 ES6-D36-LC3=40-12-18=10
4-5 1 LC5-D45-ES4=37-1-26=10 ES5-D45-ES4=27-1-26=0 Es5-D45-LC4=27-1-26=0
4-6 14 LC6-D46-ES4=40-14-26=0 ES6-D46-ES4=40-14-26=0 ES6-D46-LC4=40-14-26=0
5-6 3 LC6-D56-ES5=40-3-27=10 ES6-D56-ES5=40-3-27=10 ES6-D56-LC5=40-3-37=0
6-7 14 LC7-D67-ES6=54-14-40=0 ES7-D67-ES6=54-14-40=0 Es7-D67-LC6=54-14-40=0
Floats for critical activities are zero
• Ex2.A project consist of a series of tasks labelled A to I with
the following constraints.
• A<D, E ; B,D<F ; C<G;B,D<H;F,G<I;
• W<X,Y; means X and Y can’t start until W is completed. You
are required to construct a network diagram using this
notation. Also find the time of completion of the project ,given
the time of completion of each task.
Task A B C D E F G H I
Time
(days)
23 8 20 16 24 18 19 4 10
1
2
1
3
4
5
A(23)
B(8)
C(20
)
D(16)
E(24)
F(18
)
G(19
)
6
H(4)
I(10)
ES1=0
LC1=0
ES2=23
LC2=23
ES3=39
LC3=39
ES4=20
LC4=38
ES5=57
LC5=57
ES3=39
LC3=39
ES6=67
LC6=67
Task A B C D E F G H I
Predecessors - - - A A B,D C B,D F,G
Time 23 8 20 16 24 18 19 4 10
ESj=max(ESi+Dij), forward
pass(incoming arrow)
Values for
early start
Latest Completion LCi=min(LCj-
Dij) Backward pass(outgoing
arrow)
Values for latest
completion
ES1=0 0 LC6=ES6=67 67
ES2=Es1+D12=0+23=23 23 LC5=LC6-D56=67-10=57 57
ES3=max(ES1+D13,ES2+D23)
Max(0+8,23+16)=39
39 LC4=LC5-D45=57-19=38 38
ES4=ES1+D14=0+20=20 20 LC3=min(LC5-D35,LC6-D36)
Min(57-18,67-4)=39
39
ES5=max(Es3+D35,ES4+D45)
Max(39+18,20+19)=57
57 LC2=min(LC3-D23,LC6-D26)
Min(39-16,67-24)=23
23
ES6=max(ES2+D26,ES3+D36,ES5+D56)
Max(23+24,39+4,57+10)=67
67 LC1=min(LC2-D12,LC3-
D13,LC4-D14)
Min(23-23,39-8,38-20)=0
0
Critical path conditions:
ESi=LCi
ESj=LCj
ESj-ESi=LCj-LCi=Dij
Critical activities 1-2-3-5-6
Duration 23+16+18+10=67
critical
• Ex3.Task A to I constitute a project. The notation X<Y means
that the task X must be completed before Y is started.
• A<D;A<E;B<F;D<F;C<G;C<H;F<I;G<I. Draw a graph to
represent the sequence of tasks and find the time of
completion of the project, when the time(in days) of completion
of each tasks is as follows.
Task A B C D E F G H I
Time
(days)
8 10 8 10 16 17 18 14 9
6
5
4
3
2
1
A(8)
C(8)
B(10)
D(10
)
E(16)
F(17)
H(14
)
G(18)
I(9)
ES1=0
LC1=0
ES2=8
LC2=8
ES3=18
LC3=18
ES4=8
LC4=17
ES5=35
LC5=35
ES6=44
LC6=44
Tasks A B C D E F G H I
predecessors - - - A A B,D C C F,G
Time(days) 8 10 8 10 16 17 18 14 9
ESj=max(ESi+Dij), forward
pass(incoming arrow)
Values for
early start
Latest Completion LCi=min(LCj-
Dij) Backward pass(outgoing
arrow)
Values for latest
completion
ES1=0 0 LC6=ES6=44 44
ES2=Es1+D12=0+8=8 8 LC5=LC6-D56=44-9=35 35
ES3=max(ES1+D13,ES2+D23)
Max(0+10,8+10)=18
18 LC4=min(LC5-D45,LC6-D46)
=min(35-18,44-14)=17
17
ES4=ES1+D14=0+8=8 8 LC3=LC5-D35
35-17=18
18
ES5=max(ES3+D35,ES4+D45)
Max(18+17,8+18)=35
35 LC2=min(LC3-D23,LC6-D26)
Min(44-16,18-10)=8
8
ES6=max(ES2+D26,ES4+D46,ES5+D56)
Max(8+16,35+9,8+14)=44
44 LC1=min(LC2-D12,LC3-
D13,LC4-D14)
Min(8-8,18-10,17-8)=0
0
Critical path conditions:
Esi=LCi
ESj=LCj
ESj-ESi=LCj-LCi=Dij
Critical activities 1-2-3-5-6
Duration 8+10+17+9=44
• Example 4 .Determine the early start and late start in respect
of all node points and identify critical path for the following
network.
• Solution :Calculation of E and L for each node is shown in the
network
The critical nodes are (1, 2, 5,7,8,10)
There are two possible critical paths
i. 1 → 2 → 5 → 8 → 10
ii. 1 → 2 → 5 → 7 → 10
PERT FOR DEALING WITH
UNCERTAINTY
ESTIMATING ACTIVITY TIMES
• Optimistic time ( t0 ) : is that time estimate of an activity when everything is
assumed to go as per plan. In other words it is the estimate of minimum
possible time which an activity takes in completion under ideal conditions.
• Most likely time ( tm ) : the time which the activity will take most frequently if
repeated number of times.
• Pessimistic time ( tp) : the unlikely but possible performance time if
whatever could go wrong , goes wrong in series. In other words it is the
longest time the can take.
• The times are combined statically to develop the expected time te .
te = to + 4tm + tp
6
Standard deviation of the time of the time required to complete the project
= tp - to
6
STEPS INVOLVED IN PERT
• Develop list of activities.
• A rough network for PERT is drawn.
• Events are numbered from left to right.
• Time estimates for each activity are obtained.
• Expected time for each activity is calculated : to+4tm+tp / 6
• Using these expected times calculate earliest & latest finish &
start times of activities.
• Estimate the critical path.
• Using this estimate compute the probability of meeting a
specified completion date by using the standard normal
equation
Z = Due date – expected date of completion =Ts-Te
standard deviation of critical path δ
• Example 1:A small project is composed of 7 activities. whose
time estimates are listed in the table.
Activity 1-2 1-3 2-4 2-5 3-5 4-6 5-6
Estimated
duration(we
eks)
to 1 1 2 1 2 2 3
tm 1 4 2 1 5 5 6
tp 7 7 8 1 14 8 15
a)Draw the project network
b) Find the expected duration and variance of each activity
c)Calculate the early and late occurences for each event and the expected
project length.
d) Calculate the variance and standard deviation of project length
e)What is the probability that the project will be completed
1.4 weeks earlier than expected.
2.Not more than 4 weeks later than expected.
3.If the project due date is 19 weeks, what is the probability of meeting
the date.
Activity To tm tp Te=(to+4tm+
tp)/6
Variance 2 =[(tp-to)/6]2
1-2 1 1 7 12/6=2 6/6=(1)2=1
1-3 1 4 7 24/6=4 6/6=1
2-4 2 2 8 18/6=3 6/6=1
2-5 1 1 1 6/6=1 0
3-5 2 5 14 36/6=6 12/6= (2)2 =4
4-6 2 5 8 30/6=5 6/6=1
5-6 3 6 15 42/6=7 12/6=(2)2=4
6
4
5
3
2
1
A(2)
B(4)
C(3)
D(1)
E(6)
F(5)
G(7)
ES1=0
LC1=0
ES2=2
LC2=9
ES3=4
LC3=4
ES4=5
LC4=12
ES5=10
LC5=10
ES6=17
LC6=17
ESj=max(ESi+Dij)
LCi=min(LCj-Dij)
• c)critical path 1-3-5-6,Expected project duration:4+6+7=17weeks
Critical
activity
te Variance2
1-3 4 1
3-5 6 4
5-6 7 4
17 9
Standard deviation(SD)=sqrt(variance)
=sqrt(9)=3
d)
1)4 weeks earlier than expected
te=17 weeks ts=(17-4)=13weeks
p(Z<=D),Where D=(ts-te)/SD
D=(13-17)/3=-4/3=-1.33(SNDT)
P(Z<D)= .09176=9.17%(out of 100 times 9.1 times, project will be completed 4 weeks earlier than expected)
2)not more than 4 weeks
te=17 ts=17+4 SD=3
D=(ts-te)/SD= (21-17)/3=1.33
P(Z<=D)=0.90824=90.82%
3)te=17 ts=19 SD=3
D=19-17/3=0.67
P(Z<=D)=0.7485=74.8%
• Ex2: Find the probability of meeting the schedule date as
given for the network
Activity(i-j) 1-2 1-3 2-4 3-4 4-5 3-5
Optimistic(days) 2 9 5 2 6 8
Most likely(days) 5 12 14 5 6 17
pessimistic(days) 14 15 17 8 12 20
Find the probability that Scheduled project completion date is 30days.
Also find the date on which the project manager can complete the project
with a probability of 0.90.
Activity to tm tp Te=(to+4tm+tp)/6 Variance 2=[(tp-to)/6]2
1-2 2 5 14 36/6=6 12/6=22=4
1-3 9 12 15 72/6=12 6/6=12=1
2-4 5 14 17 78/6=13 12/6=22=4
3-4 2 5 8 30/6=5 6/6=12=1
3-5 8 17 20 96/6=16 12/6=22=4
4-5 6 6 12 42/6=7 6/6=12=1
5
4
3
2
1
A(6)
B(12
)
C(13
)
D(5)
E(16
)
B(7)
ES1=0
LC1=0
ES2=6
LC2=8
ES3=12
LC3=12
ES4=19
LC4=21
ES5=28
LC5=28
Critical path=1-3-5
Expected Project duration=12+16=28
Esj=max(ESi+Dij) and Lci=min(LCj-Dij)
activities te Variance2
1-3 12 1
3-5 16 4
28 5
SD=sqrt(5)=2.23
a)Probability of completing in 30 days, te=28 ts=30 SD=2.23
D=(ts-te)/SD=(30-28)/2.23=0.89
P(Z<=D)= .81327=81.32 %
b)Given probability=0.90, the number of days required to complete the project.
0.90 from standard normal distribution table =1.29
D=ts-te/SD=1.29
Ts-28/2.23=1.29
Ts=(1.29*2.23)+28
=30.87days
• Example 3:Consider the following project, Find the path and
standard deviation. Also find the probability of completing the
project by 18 weeks.
Activity A B C D E F G
Predecessor - - A B B C,D E
Time estimate(weeks) to 3 2 2 2 1 4 1
tm 6 5 4 3 3 6 5
tp 9 8 6 10 11 8 15
6
5
4
3
2
1
A(6)
B(5)
C(4)
D(4)
E(4)
F(6)
G(6)
ES1=0
LC1=0
ES2=6
LC2=6
ES3=5
LC3=6
ES4=10
LC4=10
ES5=9
LC5=10
ES6=16
LC6=16
Activities To(week
s)
Tm(weeks
)
Tp(weeks) Te=(to+4tm+tp)/6 Variance2=[(tp-
to)/4]2
A 3 6 9 36/6=6 1
B 2 5 8 30/6=5 1
C 2 4 6 24/6=4 0.44
D 2 3 10 24/6=4 1.77
E 1 3 11 24/6=4 2.77
F 4 6 8 36/6=6 0.44
G 1 5 15 36/6=6 5.44
Esj=max(Esi+Dij) and Lci=min(LCj-Dij)
Critical path 1-2-4-6, Expected project duration=16weeks
Critical Activities Te for critical activities Variance2 for critical activities
A 6 1
C 4 0.44
F 6 0.44
16 1.88
SD=sqrt(Variance2)=sqrt(1.88)=1.374
Probability of completing project by 18 weeks P(Z<=D)
D=(ts-te)/SD=18-16/1.374=1.455(check value from normal distribution table)
P(Z<=D)=0.92647
RESOURCE LEVELLING AND
SMOOTHING
• Resource optimization is employed when there is a resource conflict (i.e.
when the schedule requires more than the available resources) or when
there is a need to keep the resource usage at a constant level.
• Two examples of resource optimization techniques are:
1. Resource levelling and
2. Resource smoothing
• Resource smoothing is used when the time constraint takes priority. The
objective is to complete the work by the required date while avoiding peaks
and troughs of resource demand.
• Resource levelling is used when limits on the availability of resources are
dominant.
TIME-COST TRADE-OFF
• The objective of the time-cost trade-off analysis is to reduce the original
project duration, determined form the critical path analysis, to meet a specific
deadline, with the least cost. In addition to that it might be necessary to
finish the project in a specific time to:
• - Finish the project in a predefined deadline date.
• - Recover early delays.
• - Avoid liquidated damages.
• - Free key resources early for other projects.
• Avoid adverse weather conditions that might affect productivity.
• - Receive an early completion-bonus.
• - Improve project cash flow
TIME-COST TRADE-OFF CONTD..
• The activity duration can be reduced by one of the following actions:
• - Applying multiple-shifts work.
• - Working extended hours (over time).
• - Offering incentive payments to increase the productivity.
• - Working on week ends and holidays.
• - Using additional resources.
• - Using materials with faster installation methods.
• - Using alternate construction methods or sequence.
• selecting some activities on the critical path to shorten their duration.
HIGHLIGHTS
• A project is a unique, one time event of some duration that
consumes resources and is designed to achieve an objective in
a given time period.
• Each project goes through a five-phase life cycle: concept,
feasibility study, planning, execution, and termination.
• Two network planning techniques are PERT and CPM. Pert
uses probabilistic time estimates. CPM uses deterministic
time estimates.
• Pert and CPM determine the critical path of the project and
the estimated completion time. On large projects, software
programs are available to identify the critical path.
HIGHLIGHTS CON’T
• Pert uses probabilistic time estimates to determine the
probability that a project will be done by a specific time.
• To reduce the length of the project (crashing), we need to
know the critical path of the project and the cost of reducing
individual activity times. Crashing activities that are not on
the critical path typically do not reduce project completion
time.
• The critical chain approach removes excess safety time from
individual activities and creates a project buffer at the end
of the critical path.

More Related Content

What's hot

6.5 The Forward and Backward Pass (Critical Path)
6.5 The Forward and Backward Pass (Critical Path)6.5 The Forward and Backward Pass (Critical Path)
6.5 The Forward and Backward Pass (Critical Path)
DavidMcLachlan1
 
Critical Path Method (CPM) & Network Analysis
Critical Path Method (CPM) & Network AnalysisCritical Path Method (CPM) & Network Analysis
Critical Path Method (CPM) & Network Analysis
Asif Sultan Razu
 
Project networks
Project networksProject networks
Project networks
J. Scott Christianson
 
Chapter22 networktechniquesforprojectmanagement
Chapter22 networktechniquesforprojectmanagementChapter22 networktechniquesforprojectmanagement
Chapter22 networktechniquesforprojectmanagement
AKSHAYA0000
 
Critical Path Ppt
Critical Path PptCritical Path Ppt
Critical Path Ppt
Jeff Hilton
 
Project management Pert & cpm
Project management Pert & cpm Project management Pert & cpm
Project management Pert & cpm
RandhirKumar172
 
Pert & cpm project management
Pert & cpm   project managementPert & cpm   project management
Pert & cpm project managementRahul Dubey
 
Pert and CPM
Pert and CPMPert and CPM
Pert and CPM
Sachin Kapoor
 
06 pert cpm
06 pert cpm06 pert cpm
06 pert cpm
BLESSY ALOSHIOUS
 
Network Techniques for Project Management
Network Techniques for Project ManagementNetwork Techniques for Project Management
Network Techniques for Project Management
Ishan Gandhi
 
Critical path method
Critical path methodCritical path method
Critical path method
Dushyant Nasit
 
Network diagram problems
Network diagram problemsNetwork diagram problems
Network diagram problems
Subhra Mishra
 
Rules for Network Construction
Rules for Network ConstructionRules for Network Construction
Rules for Network Construction
Raja Adapa
 
Forms of Project Organization
Forms of Project OrganizationForms of Project Organization
Forms of Project Organization
Gautam Chopra
 
Cpm n pert lecture 1
Cpm n pert lecture 1Cpm n pert lecture 1
Cpm n pert lecture 1
adeelmunir158
 
Project management & Network analysis
Project management & Network analysisProject management & Network analysis
Project management & Network analysisHarinadh Karimikonda
 
Work breakdown structure ppt
Work breakdown structure pptWork breakdown structure ppt
Work breakdown structure pptnazi2020
 

What's hot (20)

Pert
PertPert
Pert
 
6.5 The Forward and Backward Pass (Critical Path)
6.5 The Forward and Backward Pass (Critical Path)6.5 The Forward and Backward Pass (Critical Path)
6.5 The Forward and Backward Pass (Critical Path)
 
Critical Path Method (CPM) & Network Analysis
Critical Path Method (CPM) & Network AnalysisCritical Path Method (CPM) & Network Analysis
Critical Path Method (CPM) & Network Analysis
 
Project networks
Project networksProject networks
Project networks
 
Chapter22 networktechniquesforprojectmanagement
Chapter22 networktechniquesforprojectmanagementChapter22 networktechniquesforprojectmanagement
Chapter22 networktechniquesforprojectmanagement
 
Critical Path Ppt
Critical Path PptCritical Path Ppt
Critical Path Ppt
 
Project management Pert & cpm
Project management Pert & cpm Project management Pert & cpm
Project management Pert & cpm
 
Pert & cpm project management
Pert & cpm   project managementPert & cpm   project management
Pert & cpm project management
 
Pert and CPM
Pert and CPMPert and CPM
Pert and CPM
 
06 pert cpm
06 pert cpm06 pert cpm
06 pert cpm
 
Network Techniques for Project Management
Network Techniques for Project ManagementNetwork Techniques for Project Management
Network Techniques for Project Management
 
Critical path method
Critical path methodCritical path method
Critical path method
 
Network diagram problems
Network diagram problemsNetwork diagram problems
Network diagram problems
 
Rules for Network Construction
Rules for Network ConstructionRules for Network Construction
Rules for Network Construction
 
Forms of Project Organization
Forms of Project OrganizationForms of Project Organization
Forms of Project Organization
 
Cpm n pert lecture 1
Cpm n pert lecture 1Cpm n pert lecture 1
Cpm n pert lecture 1
 
Chap06 project time management
Chap06 project time managementChap06 project time management
Chap06 project time management
 
Project management & Network analysis
Project management & Network analysisProject management & Network analysis
Project management & Network analysis
 
Pert & Cpm
Pert & CpmPert & Cpm
Pert & Cpm
 
Work breakdown structure ppt
Work breakdown structure pptWork breakdown structure ppt
Work breakdown structure ppt
 

Similar to Unit2 network optimization

Project management
Project managementProject management
Project management
Jyoti Prakash Singh
 
Session 9 - Project scheduling-PERT-CPM-Network diagram.pptx
Session 9 - Project scheduling-PERT-CPM-Network diagram.pptxSession 9 - Project scheduling-PERT-CPM-Network diagram.pptx
Session 9 - Project scheduling-PERT-CPM-Network diagram.pptx
AlRashedinKawser2
 
Short Comings of Bar Chart and Remidial Measures
Short Comings of Bar Chart and Remidial MeasuresShort Comings of Bar Chart and Remidial Measures
Short Comings of Bar Chart and Remidial Measures
sudheerkumar_nitw
 
08. Project Time Management Upload
08. Project Time Management Upload08. Project Time Management Upload
08. Project Time Management Upload
BhuWan Khadka
 
L2_Project_Management.pdf
L2_Project_Management.pdfL2_Project_Management.pdf
L2_Project_Management.pdf
JerryHung19
 
PERT-CPM PPT.pptx
PERT-CPM PPT.pptxPERT-CPM PPT.pptx
PERT-CPM PPT.pptx
DhesinghRajaLekha
 
Critical Path Method: Activities And Events, Float/Slacks
Critical Path Method: Activities And Events, Float/SlacksCritical Path Method: Activities And Events, Float/Slacks
Critical Path Method: Activities And Events, Float/Slacks
Prasad Thanthratey
 
Chap 4- CPM & PERT.pptx
Chap 4- CPM & PERT.pptxChap 4- CPM & PERT.pptx
Chap 4- CPM & PERT.pptx
mohammad_bilal
 
Project Management.pptx
Project Management.pptxProject Management.pptx
Project Management.pptx
AakankshaSinghRathor
 
Project management.pptx
Project management.pptxProject management.pptx
Project management.pptx
MaulikVasani1
 
CPM, Network Analysis A-O-A, A-O-N, Resource management
CPM, Network Analysis A-O-A, A-O-N, Resource managementCPM, Network Analysis A-O-A, A-O-N, Resource management
CPM, Network Analysis A-O-A, A-O-N, Resource management
Amit Kumbar
 
Pert cpm SIDDANNA M BALAPGOL
Pert cpm SIDDANNA M BALAPGOLPert cpm SIDDANNA M BALAPGOL
Pert cpm SIDDANNA M BALAPGOL
Siddanna Balapgol
 
Software engineering ppt on pert and gantt charts
Software engineering ppt on pert and gantt chartsSoftware engineering ppt on pert and gantt charts
Software engineering ppt on pert and gantt charts
GovadaDhana
 
Unit 02 unit – ii project planning and scheduling
Unit 02 unit – ii project planning and schedulingUnit 02 unit – ii project planning and scheduling
Unit 02 unit – ii project planning and scheduling
RAMCHANDRA KODAM
 
PERT AND CPM PROJECT MANAGEMENT
PERT AND CPM PROJECT MANAGEMENTPERT AND CPM PROJECT MANAGEMENT
PERT AND CPM PROJECT MANAGEMENT
salsa moyara
 
project network
project networkproject network
project network
Sougata Das
 
criticalpathmethod-151022164503-lva1-app6892.pdf
criticalpathmethod-151022164503-lva1-app6892.pdfcriticalpathmethod-151022164503-lva1-app6892.pdf
criticalpathmethod-151022164503-lva1-app6892.pdf
Salahudin Babar
 
Cpm (critical path method)
Cpm (critical path method)Cpm (critical path method)
Cpm (critical path method)
Areef Khan
 

Similar to Unit2 network optimization (20)

Project management
Project managementProject management
Project management
 
Session 9 - Project scheduling-PERT-CPM-Network diagram.pptx
Session 9 - Project scheduling-PERT-CPM-Network diagram.pptxSession 9 - Project scheduling-PERT-CPM-Network diagram.pptx
Session 9 - Project scheduling-PERT-CPM-Network diagram.pptx
 
Short Comings of Bar Chart and Remidial Measures
Short Comings of Bar Chart and Remidial MeasuresShort Comings of Bar Chart and Remidial Measures
Short Comings of Bar Chart and Remidial Measures
 
08. Project Time Management Upload
08. Project Time Management Upload08. Project Time Management Upload
08. Project Time Management Upload
 
L2_Project_Management.pdf
L2_Project_Management.pdfL2_Project_Management.pdf
L2_Project_Management.pdf
 
PERT-CPM PPT.pptx
PERT-CPM PPT.pptxPERT-CPM PPT.pptx
PERT-CPM PPT.pptx
 
Critical Path Method: Activities And Events, Float/Slacks
Critical Path Method: Activities And Events, Float/SlacksCritical Path Method: Activities And Events, Float/Slacks
Critical Path Method: Activities And Events, Float/Slacks
 
Chap 4- CPM & PERT.pptx
Chap 4- CPM & PERT.pptxChap 4- CPM & PERT.pptx
Chap 4- CPM & PERT.pptx
 
Chapter 07
Chapter 07Chapter 07
Chapter 07
 
Project Management.pptx
Project Management.pptxProject Management.pptx
Project Management.pptx
 
Ch 5.pptx
Ch 5.pptxCh 5.pptx
Ch 5.pptx
 
Project management.pptx
Project management.pptxProject management.pptx
Project management.pptx
 
CPM, Network Analysis A-O-A, A-O-N, Resource management
CPM, Network Analysis A-O-A, A-O-N, Resource managementCPM, Network Analysis A-O-A, A-O-N, Resource management
CPM, Network Analysis A-O-A, A-O-N, Resource management
 
Pert cpm SIDDANNA M BALAPGOL
Pert cpm SIDDANNA M BALAPGOLPert cpm SIDDANNA M BALAPGOL
Pert cpm SIDDANNA M BALAPGOL
 
Software engineering ppt on pert and gantt charts
Software engineering ppt on pert and gantt chartsSoftware engineering ppt on pert and gantt charts
Software engineering ppt on pert and gantt charts
 
Unit 02 unit – ii project planning and scheduling
Unit 02 unit – ii project planning and schedulingUnit 02 unit – ii project planning and scheduling
Unit 02 unit – ii project planning and scheduling
 
PERT AND CPM PROJECT MANAGEMENT
PERT AND CPM PROJECT MANAGEMENTPERT AND CPM PROJECT MANAGEMENT
PERT AND CPM PROJECT MANAGEMENT
 
project network
project networkproject network
project network
 
criticalpathmethod-151022164503-lva1-app6892.pdf
criticalpathmethod-151022164503-lva1-app6892.pdfcriticalpathmethod-151022164503-lva1-app6892.pdf
criticalpathmethod-151022164503-lva1-app6892.pdf
 
Cpm (critical path method)
Cpm (critical path method)Cpm (critical path method)
Cpm (critical path method)
 

More from DevaKumari Vijay

Unit 1 computer architecture (1)
Unit 1   computer architecture (1)Unit 1   computer architecture (1)
Unit 1 computer architecture (1)
DevaKumari Vijay
 
Os ch1
Os ch1Os ch1
Unit2
Unit2Unit2
Unit 1
Unit 1Unit 1
Unit 2 monte carlo simulation
Unit 2 monte carlo simulationUnit 2 monte carlo simulation
Unit 2 monte carlo simulation
DevaKumari Vijay
 
Decisiontree&amp;game theory
Decisiontree&amp;game theoryDecisiontree&amp;game theory
Decisiontree&amp;game theory
DevaKumari Vijay
 
Unit 4 simulation and queing theory(m/m/1)
Unit 4  simulation and queing theory(m/m/1)Unit 4  simulation and queing theory(m/m/1)
Unit 4 simulation and queing theory(m/m/1)
DevaKumari Vijay
 
Unit4 systemdynamics
Unit4 systemdynamicsUnit4 systemdynamics
Unit4 systemdynamics
DevaKumari Vijay
 
Unit 3 des
Unit 3 desUnit 3 des
Unit 3 des
DevaKumari Vijay
 
Unit 1 introduction to simulation
Unit 1 introduction to simulationUnit 1 introduction to simulation
Unit 1 introduction to simulation
DevaKumari Vijay
 
Unit2 montecarlosimulation
Unit2 montecarlosimulationUnit2 montecarlosimulation
Unit2 montecarlosimulation
DevaKumari Vijay
 
Unit 3-Greedy Method
Unit 3-Greedy MethodUnit 3-Greedy Method
Unit 3-Greedy Method
DevaKumari Vijay
 
Unit 5 java-awt (1)
Unit 5 java-awt (1)Unit 5 java-awt (1)
Unit 5 java-awt (1)
DevaKumari Vijay
 
Unit 4 exceptions and threads
Unit 4 exceptions and threadsUnit 4 exceptions and threads
Unit 4 exceptions and threads
DevaKumari Vijay
 
Unit3 part3-packages and interfaces
Unit3 part3-packages and interfacesUnit3 part3-packages and interfaces
Unit3 part3-packages and interfaces
DevaKumari Vijay
 
Unit3 part2-inheritance
Unit3 part2-inheritanceUnit3 part2-inheritance
Unit3 part2-inheritance
DevaKumari Vijay
 
Unit3 part1-class
Unit3 part1-classUnit3 part1-class
Unit3 part1-class
DevaKumari Vijay
 
Unit 2-data types,Variables,Operators,Conitionals,loops and arrays
Unit 2-data types,Variables,Operators,Conitionals,loops and arraysUnit 2-data types,Variables,Operators,Conitionals,loops and arrays
Unit 2-data types,Variables,Operators,Conitionals,loops and arrays
DevaKumari Vijay
 
Unit1 introduction to Java
Unit1 introduction to JavaUnit1 introduction to Java
Unit1 introduction to Java
DevaKumari Vijay
 
Introduction to design and analysis of algorithm
Introduction to design and analysis of algorithmIntroduction to design and analysis of algorithm
Introduction to design and analysis of algorithm
DevaKumari Vijay
 

More from DevaKumari Vijay (20)

Unit 1 computer architecture (1)
Unit 1   computer architecture (1)Unit 1   computer architecture (1)
Unit 1 computer architecture (1)
 
Os ch1
Os ch1Os ch1
Os ch1
 
Unit2
Unit2Unit2
Unit2
 
Unit 1
Unit 1Unit 1
Unit 1
 
Unit 2 monte carlo simulation
Unit 2 monte carlo simulationUnit 2 monte carlo simulation
Unit 2 monte carlo simulation
 
Decisiontree&amp;game theory
Decisiontree&amp;game theoryDecisiontree&amp;game theory
Decisiontree&amp;game theory
 
Unit 4 simulation and queing theory(m/m/1)
Unit 4  simulation and queing theory(m/m/1)Unit 4  simulation and queing theory(m/m/1)
Unit 4 simulation and queing theory(m/m/1)
 
Unit4 systemdynamics
Unit4 systemdynamicsUnit4 systemdynamics
Unit4 systemdynamics
 
Unit 3 des
Unit 3 desUnit 3 des
Unit 3 des
 
Unit 1 introduction to simulation
Unit 1 introduction to simulationUnit 1 introduction to simulation
Unit 1 introduction to simulation
 
Unit2 montecarlosimulation
Unit2 montecarlosimulationUnit2 montecarlosimulation
Unit2 montecarlosimulation
 
Unit 3-Greedy Method
Unit 3-Greedy MethodUnit 3-Greedy Method
Unit 3-Greedy Method
 
Unit 5 java-awt (1)
Unit 5 java-awt (1)Unit 5 java-awt (1)
Unit 5 java-awt (1)
 
Unit 4 exceptions and threads
Unit 4 exceptions and threadsUnit 4 exceptions and threads
Unit 4 exceptions and threads
 
Unit3 part3-packages and interfaces
Unit3 part3-packages and interfacesUnit3 part3-packages and interfaces
Unit3 part3-packages and interfaces
 
Unit3 part2-inheritance
Unit3 part2-inheritanceUnit3 part2-inheritance
Unit3 part2-inheritance
 
Unit3 part1-class
Unit3 part1-classUnit3 part1-class
Unit3 part1-class
 
Unit 2-data types,Variables,Operators,Conitionals,loops and arrays
Unit 2-data types,Variables,Operators,Conitionals,loops and arraysUnit 2-data types,Variables,Operators,Conitionals,loops and arrays
Unit 2-data types,Variables,Operators,Conitionals,loops and arrays
 
Unit1 introduction to Java
Unit1 introduction to JavaUnit1 introduction to Java
Unit1 introduction to Java
 
Introduction to design and analysis of algorithm
Introduction to design and analysis of algorithmIntroduction to design and analysis of algorithm
Introduction to design and analysis of algorithm
 

Recently uploaded

BÀI TẬP BỔ TRỢ TIẾNG ANH GLOBAL SUCCESS LỚP 3 - CẢ NĂM (CÓ FILE NGHE VÀ ĐÁP Á...
BÀI TẬP BỔ TRỢ TIẾNG ANH GLOBAL SUCCESS LỚP 3 - CẢ NĂM (CÓ FILE NGHE VÀ ĐÁP Á...BÀI TẬP BỔ TRỢ TIẾNG ANH GLOBAL SUCCESS LỚP 3 - CẢ NĂM (CÓ FILE NGHE VÀ ĐÁP Á...
BÀI TẬP BỔ TRỢ TIẾNG ANH GLOBAL SUCCESS LỚP 3 - CẢ NĂM (CÓ FILE NGHE VÀ ĐÁP Á...
Nguyen Thanh Tu Collection
 
CLASS 11 CBSE B.St Project AIDS TO TRADE - INSURANCE
CLASS 11 CBSE B.St Project AIDS TO TRADE - INSURANCECLASS 11 CBSE B.St Project AIDS TO TRADE - INSURANCE
CLASS 11 CBSE B.St Project AIDS TO TRADE - INSURANCE
BhavyaRajput3
 
How libraries can support authors with open access requirements for UKRI fund...
How libraries can support authors with open access requirements for UKRI fund...How libraries can support authors with open access requirements for UKRI fund...
How libraries can support authors with open access requirements for UKRI fund...
Jisc
 
Thesis Statement for students diagnonsed withADHD.ppt
Thesis Statement for students diagnonsed withADHD.pptThesis Statement for students diagnonsed withADHD.ppt
Thesis Statement for students diagnonsed withADHD.ppt
EverAndrsGuerraGuerr
 
Supporting (UKRI) OA monographs at Salford.pptx
Supporting (UKRI) OA monographs at Salford.pptxSupporting (UKRI) OA monographs at Salford.pptx
Supporting (UKRI) OA monographs at Salford.pptx
Jisc
 
Model Attribute Check Company Auto Property
Model Attribute  Check Company Auto PropertyModel Attribute  Check Company Auto Property
Model Attribute Check Company Auto Property
Celine George
 
The Accursed House by Émile Gaboriau.pptx
The Accursed House by Émile Gaboriau.pptxThe Accursed House by Émile Gaboriau.pptx
The Accursed House by Émile Gaboriau.pptx
DhatriParmar
 
Instructions for Submissions thorugh G- Classroom.pptx
Instructions for Submissions thorugh G- Classroom.pptxInstructions for Submissions thorugh G- Classroom.pptx
Instructions for Submissions thorugh G- Classroom.pptx
Jheel Barad
 
Polish students' mobility in the Czech Republic
Polish students' mobility in the Czech RepublicPolish students' mobility in the Czech Republic
Polish students' mobility in the Czech Republic
Anna Sz.
 
Guidance_and_Counselling.pdf B.Ed. 4th Semester
Guidance_and_Counselling.pdf B.Ed. 4th SemesterGuidance_and_Counselling.pdf B.Ed. 4th Semester
Guidance_and_Counselling.pdf B.Ed. 4th Semester
Atul Kumar Singh
 
"Protectable subject matters, Protection in biotechnology, Protection of othe...
"Protectable subject matters, Protection in biotechnology, Protection of othe..."Protectable subject matters, Protection in biotechnology, Protection of othe...
"Protectable subject matters, Protection in biotechnology, Protection of othe...
SACHIN R KONDAGURI
 
A Strategic Approach: GenAI in Education
A Strategic Approach: GenAI in EducationA Strategic Approach: GenAI in Education
A Strategic Approach: GenAI in Education
Peter Windle
 
Sha'Carri Richardson Presentation 202345
Sha'Carri Richardson Presentation 202345Sha'Carri Richardson Presentation 202345
Sha'Carri Richardson Presentation 202345
beazzy04
 
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
siemaillard
 
Additional Benefits for Employee Website.pdf
Additional Benefits for Employee Website.pdfAdditional Benefits for Employee Website.pdf
Additional Benefits for Employee Website.pdf
joachimlavalley1
 
678020731-Sumas-y-Restas-Para-Colorear.pdf
678020731-Sumas-y-Restas-Para-Colorear.pdf678020731-Sumas-y-Restas-Para-Colorear.pdf
678020731-Sumas-y-Restas-Para-Colorear.pdf
CarlosHernanMontoyab2
 
2024.06.01 Introducing a competency framework for languag learning materials ...
2024.06.01 Introducing a competency framework for languag learning materials ...2024.06.01 Introducing a competency framework for languag learning materials ...
2024.06.01 Introducing a competency framework for languag learning materials ...
Sandy Millin
 
The approach at University of Liverpool.pptx
The approach at University of Liverpool.pptxThe approach at University of Liverpool.pptx
The approach at University of Liverpool.pptx
Jisc
 
Introduction to AI for Nonprofits with Tapp Network
Introduction to AI for Nonprofits with Tapp NetworkIntroduction to AI for Nonprofits with Tapp Network
Introduction to AI for Nonprofits with Tapp Network
TechSoup
 
Language Across the Curriculm LAC B.Ed.
Language Across the  Curriculm LAC B.Ed.Language Across the  Curriculm LAC B.Ed.
Language Across the Curriculm LAC B.Ed.
Atul Kumar Singh
 

Recently uploaded (20)

BÀI TẬP BỔ TRỢ TIẾNG ANH GLOBAL SUCCESS LỚP 3 - CẢ NĂM (CÓ FILE NGHE VÀ ĐÁP Á...
BÀI TẬP BỔ TRỢ TIẾNG ANH GLOBAL SUCCESS LỚP 3 - CẢ NĂM (CÓ FILE NGHE VÀ ĐÁP Á...BÀI TẬP BỔ TRỢ TIẾNG ANH GLOBAL SUCCESS LỚP 3 - CẢ NĂM (CÓ FILE NGHE VÀ ĐÁP Á...
BÀI TẬP BỔ TRỢ TIẾNG ANH GLOBAL SUCCESS LỚP 3 - CẢ NĂM (CÓ FILE NGHE VÀ ĐÁP Á...
 
CLASS 11 CBSE B.St Project AIDS TO TRADE - INSURANCE
CLASS 11 CBSE B.St Project AIDS TO TRADE - INSURANCECLASS 11 CBSE B.St Project AIDS TO TRADE - INSURANCE
CLASS 11 CBSE B.St Project AIDS TO TRADE - INSURANCE
 
How libraries can support authors with open access requirements for UKRI fund...
How libraries can support authors with open access requirements for UKRI fund...How libraries can support authors with open access requirements for UKRI fund...
How libraries can support authors with open access requirements for UKRI fund...
 
Thesis Statement for students diagnonsed withADHD.ppt
Thesis Statement for students diagnonsed withADHD.pptThesis Statement for students diagnonsed withADHD.ppt
Thesis Statement for students diagnonsed withADHD.ppt
 
Supporting (UKRI) OA monographs at Salford.pptx
Supporting (UKRI) OA monographs at Salford.pptxSupporting (UKRI) OA monographs at Salford.pptx
Supporting (UKRI) OA monographs at Salford.pptx
 
Model Attribute Check Company Auto Property
Model Attribute  Check Company Auto PropertyModel Attribute  Check Company Auto Property
Model Attribute Check Company Auto Property
 
The Accursed House by Émile Gaboriau.pptx
The Accursed House by Émile Gaboriau.pptxThe Accursed House by Émile Gaboriau.pptx
The Accursed House by Émile Gaboriau.pptx
 
Instructions for Submissions thorugh G- Classroom.pptx
Instructions for Submissions thorugh G- Classroom.pptxInstructions for Submissions thorugh G- Classroom.pptx
Instructions for Submissions thorugh G- Classroom.pptx
 
Polish students' mobility in the Czech Republic
Polish students' mobility in the Czech RepublicPolish students' mobility in the Czech Republic
Polish students' mobility in the Czech Republic
 
Guidance_and_Counselling.pdf B.Ed. 4th Semester
Guidance_and_Counselling.pdf B.Ed. 4th SemesterGuidance_and_Counselling.pdf B.Ed. 4th Semester
Guidance_and_Counselling.pdf B.Ed. 4th Semester
 
"Protectable subject matters, Protection in biotechnology, Protection of othe...
"Protectable subject matters, Protection in biotechnology, Protection of othe..."Protectable subject matters, Protection in biotechnology, Protection of othe...
"Protectable subject matters, Protection in biotechnology, Protection of othe...
 
A Strategic Approach: GenAI in Education
A Strategic Approach: GenAI in EducationA Strategic Approach: GenAI in Education
A Strategic Approach: GenAI in Education
 
Sha'Carri Richardson Presentation 202345
Sha'Carri Richardson Presentation 202345Sha'Carri Richardson Presentation 202345
Sha'Carri Richardson Presentation 202345
 
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
 
Additional Benefits for Employee Website.pdf
Additional Benefits for Employee Website.pdfAdditional Benefits for Employee Website.pdf
Additional Benefits for Employee Website.pdf
 
678020731-Sumas-y-Restas-Para-Colorear.pdf
678020731-Sumas-y-Restas-Para-Colorear.pdf678020731-Sumas-y-Restas-Para-Colorear.pdf
678020731-Sumas-y-Restas-Para-Colorear.pdf
 
2024.06.01 Introducing a competency framework for languag learning materials ...
2024.06.01 Introducing a competency framework for languag learning materials ...2024.06.01 Introducing a competency framework for languag learning materials ...
2024.06.01 Introducing a competency framework for languag learning materials ...
 
The approach at University of Liverpool.pptx
The approach at University of Liverpool.pptxThe approach at University of Liverpool.pptx
The approach at University of Liverpool.pptx
 
Introduction to AI for Nonprofits with Tapp Network
Introduction to AI for Nonprofits with Tapp NetworkIntroduction to AI for Nonprofits with Tapp Network
Introduction to AI for Nonprofits with Tapp Network
 
Language Across the Curriculm LAC B.Ed.
Language Across the  Curriculm LAC B.Ed.Language Across the  Curriculm LAC B.Ed.
Language Across the Curriculm LAC B.Ed.
 

Unit2 network optimization

  • 2. PROJECT MANAGEMENT APPLICATIONS • What is a project? • Any unique endeavor with specific objectives • With multiple activities • With defined precedent relationships • With a specific time period for completion • Phases:Planning,scheduling and controlling • Examples? • A major event like a wedding • Any construction project • Designing a political campaign
  • 3. PROJECT LIFE CYCLE • Conception: identify the need • Feasibility analysis or study: costs benefits, and risks • Planning: who, how long, what to do?, objective and assumptions, listing the tasks, cost/time estimation • Scheduling: laying the activity according to precedence Start and end time for each activity, critical path, floats and slacks • Controlling: periodical progress reports, review • Execution: doing the project • Termination: ending the project
  • 4. NETWORK PLANNING TECHNIQUES • A network is a graphic representation of a project’s operations and a composed of activities and events that must be completed to reach the end objective of a project, showing the planning sequence of time accomplishment, their dependence and inter-relationship • Program Evaluation & Review Technique (PERT): • Developed to manage the Polaris missile project • Many tasks pushed the boundaries of science & engineering (tasks’ duration = probabilistic) • Critical Path Method (CPM): • Developed to coordinate maintenance projects in the chemical industry • A complex undertaking, but individual tasks are routine (tasks’ duration = deterministic)
  • 5. • The basic components of a network are • Activity- An activity is a task, or item of work to be done, that consume time, effort, money or other resources. An activity is represented by an arrow with its head indicating the sequence in which the events are to occur. • Event- An event represents the start (beginning) or completion (end) of some activity and as such it consume no time. It has no time duration and does not consume any resources. It is also known as a node. An event is generally represented on the network by a circle.
  • 6. • The activity can be further classified into the following three categories • 1. Predecessor activity- An activity which must be completed before one or more other activities start is known as predecessor activity • 2. Successor activity- An activity which started immediately after one or more of other activities are completed is known as successor activity. • 3. Dummy activity- An activity which does not consume either any resource or time is known as dummy activity. A dummy activity is depicted by dotted line in the network diagram • The dummy activity is inserted in the network to clarify the activity pattern in the following two situations To make activities with common starting and finishing points distinguishable To identify and maintain the proper precedence relationship between activities that is not connected by events. For example, consider a situation where A and B are concurrent activities. C is dependent on A and D is dependent on A and B both. Such a situation can be handled by using a dummy activity as shown in the figure. 1 2 3 4
  • 7. • The events are classified in to three categories • 1. Merge event – When more than one activity comes and joins an event such an event is known as merge event. • 2. Burst event – When more than one activity leaves an event such an event is known as burst event. • 3. Merge and Burst event – An activity may be merge and burst event at the same time as with respect to some activities it can be a merge event and with respect to some other activities it may be a burst event.
  • 8. • Logical sequences in Network diagram: • All the projects consist of certain activities that can begin only after certain others are completed. • In logical sequencing, following two types of errors are most common while drawing a network diagram. • 1. Looping: No Activity should start and end on same event. • 2. Dangling- No activity should end without being joined to the end event. If it is not so, a dummy activity is introduced in order to maintain the continuity of the system. Such end event other than the end of the project as a whole are called dangling events.
  • 9. • Rules for Network Representation • Three rules are available for constructing the network • 1. Each activity is represented by one, and only one arrow (arc) • 2. Each activity must be identified by two distinct end nodes & no two or more activities can have the same tail. • 3. To maintain the correct precedence relationships, the following questions must be answered as each is added to network: • (a) What activities must immediately precede the current activity? • (b) What activities must follow the current activity? ( • c) What activities must occur concurrently with the current activity? • The answer of these questions may require the use of dummy activities to ensure correct precedences among the activities. • Numbering the events • (a) Event numbers should be unique • (b) Event numbering should be carried out on a sequential basis from left to right • (c) The initial event which has all outgoing arrows with no incoming arrow is numbered 0 or 1 • (d) The head of an arrow should always bear a number higher than the one assigned at the tail of the arrow
  • 10. • Example 1:Costruct the network diagram for the project with the following activities Activities A B C D E F G Predecessor - - - A B C D
  • 11. BOTH PERT AND CPM • Graphically display the precedence relationships & sequence of activities • Estimate the project’s duration • Identify critical activities that cannot be delayed without delaying the project • Estimate the amount of slack associated with non-critical activities
  • 12. • The major differences between PERT and CPM are summarized as given below • PERT • Event oriented • Probabilistic in nature • Concerned with time • Used for new projects • CPM • Activity oriented • Deterministic in nature • Concerned with time and cost • Used for repetitive projects
  • 13. CRITICAL PATH METHOD IN NETWORK ANALYSIS • The notations used are • (i, j) = Activity with tail event i and head event j • Ei = Earliest occurrence time of event I • Lj = Latest allowable occurrence time of event j • Dij = Duration of activity (i, j) • (Es)ij = Earliest starting time of activity (i, j) • (Ef)ij = Earliest finishing time of activity (i, j) • (Ls)ij = Latest starting time of activity (i, j) • (Lf)ij = Latest finishing time of activity (i, j)
  • 14. • Forward Pass computation • Step 1 :The computation begins from the start node and move towards the end node. Set E1 = 0 to indicate that the project starts at time 0 • Step 2 • i. Earliest starting time of activity (i, j) is the earliest event time of the tail end event i.e. (Es)ij = Ei • ii. Earliest finish time of activity (i, j) is the earliest starting time + the activity time i.e. (Ef)ij = (Es)ij + Dij or (Ef)ij = Ei + Dij • iii. Earliest event time for event j is the maximum of the earliest finish times of all activities ending in to that event i.e. Ej = max [(Ef)ij for all immediate predecessor of (i, j)] or Ej =max [Ei + Dij]
  • 15. • Backward Pass computation (for latest allowable time) • Step 1 :For ending event assume E = L. (Remember that all E’s have been computed by forward pass computations)to indicate that the earliest and latest occurrences of the last node of the project are the same. • Step 2 :Latest finish time for activity (i, j) is equal to the latest event time of event j i.e. (Lf)ij = Lj • Step 3 :Latest starting time of activity (i, j) = the latest completion time of (i, j) – the activity time or (Ls)ij =(Lf)ij - Dij or (Ls)ij = Lj – Dij • Step 4 :Latest event time for event ‘i’ is the minimum of the latest start time of all activities originating from that event i.e. Li = min [(Ls)ij for all immediate successor of (i, j)] = min [(Lf)ij - Dij] = min [Lj - Dij]
  • 16. DETERMINATION OF FLOATS AND SLACK TIMES • In case of non-critical activities, certain amount of spare time is available and this spare time is called “float”. There are three type of float • Total float – The amount of time by which the completion of an activity could be delayed beyond the earliest expected completion time without affecting the overall project duration time. Mathematically (Tf)ij = (Latest start – Earliest start) for activity ( i – j) (Tf)ij = (LFj - (ES)i-Dij or (Tf)ij = (Lj - Dij) - Ei
  • 17. • Free float – The time by which the completion of an activity can be delayed beyond the earliest finish time without affecting the earliest start of a subsequent activity. Mathematically (Ff)ij = (Earliest time for event j – Earliest time for event i) – Activity time for ( i, j) (Ff)ij = (Ej - Ei) - Dij • Independent float – The amount of time by which the start of an activity can be delayed without effecting the earliest start time of any immediately following activities, assuming that the preceding activity has finished at its latest finish time. Mathematically (If)ij = (Ej - Li) - Dij The negative independent float is always taken as zero. • Event slack - It is defined as the difference between the latest event and earliest event times. Mathematically Head event slack = Lj – Ej , Tail event slack = Li – Ei Critical event – The events with zero slack times are called critical events. In other words the event i is said to be critical if Ei = Li Critical activity – The activities with zero total float are known as critical activities. Critical path – The sequence of critical activities in a network is called critical path.
  • 18. SOME NETWORK DEFINITIONS • All activities on the critical path have zero slack • Slack defines how long non-critical activities can be delayed without delaying the project • Slack = the activity’s late finish minus its early finish (or its late start minus its early start) • Earliest Start (ES) = the earliest finish of the immediately preceding activity • Earliest Finish (EF) = is the ES plus the activity time • Latest Start (LS) and Latest Finish (LF) = the latest an activity can start (LS) or finish (LF) without delaying the project completion
  • 19. • Ex1.A small maintenance project consist of the following jobs whose precedence relationship is given below Job 1-2 1-3 2-3 2-5 3-4 3-6 4-5 4-6 5-6 6-7 Duration (days) 15 15 3 5 8 12 1 14 3 14 a)Draw an arrow diagram representing the project b)Find the total float for each activity c)Find the critical path and the total project duration
  • 20. Early start(ES) for forward pass(incoming arrows) ESj=Max(ESi+Dij) value ES1=0 0 ES2=ES1+D12 0+15 15 ES3=max(ES1+D13,ES2+D23) Max(0+15,15+3) 18 ES4=ES3+D34 18+8 26 ES5=max(ES2+D25,ES4+D45) Max(15+5,26+1) 27 Es6=max(ES3+D36,ES4+D46,ES5+D56) Max(18+12,26+14,27+3) 40 ES7=ES6+D67 40+14 54 1 2 3 4 5 6 7 A(15) B(15 )) C(3) D(5) E(8) F(12 ) G(1) H(14 ) I(3) J(14) ES1=0 LC1=0 E ES3=18 LC3=18 ES4=26 LC4=26 ES5=27 LC5=37 ES6=40 LC6=40 ES7=54 LC7=54
  • 21. Latest Complete(LC) for Backward pass(Outgoing arrows) LCi=min(LCj-Dij) value LC7=ES7 54 LC6=LC7-D67 54-14 40 LC5=LC6-D56 40-3 37 LC4=min(LC5-D45,LC6-D46) =min(37-1,40-14) 40-14 26 LC3=min(LC4-D34,LC6-D36) =min(26-8,40-12) 26-8 18 LC2=min(LC3-D23,LC5-D25) =min(18-3,37-5) 18-3 15 LC1=min(LC2-D12,LC3-D13) =min(15-15,18-15) 15-15 0 c)Critical Path conditions 1.ESi=LCi 2.ESj=LCj 3.ESj-ESi=Dij Critical path:1-2-3-4-6-7 Project duration=15+3+8+14+14=54days
  • 22. Activity Duration Total float=LCj-Dij-Esi Free Float=ESj-Dij-ESi Independent float=ESj-Dij- LCi 1-2 15 LC2-D12-ES1=15-15-0=0 ES2-D12-Es1=15-15-0=0 ES2-D12-LC1=15-15-0=0 1-3 15 LC3-D13-ES1=18-15-0=3 ES3-D13-ES1=18-15-0=3 ES3-D13-LC1=18-15-0=3 2-3 3 LC3-D23-ES2=18-3-15=0 ES3-D23-ES2=18-3-15=0 ES3-D23-LC2=18-3-15=0 2-5 5 LC5-D25-ES2=37-5-15=17 ES5-D25-ES2=27-5-15=7 ES5-D25-LC2=27-5-15=7 3-4 8 LC4-D34-ES3=26-8-18=0 ES4-D34-ES3=26-8-18=0 ES4-D34-LC3=26-8-18=0 3-6 12 LC6-D36-ES3=40-12-18=10 ES6-D36-ES3=40-12-18=10 ES6-D36-LC3=40-12-18=10 4-5 1 LC5-D45-ES4=37-1-26=10 ES5-D45-ES4=27-1-26=0 Es5-D45-LC4=27-1-26=0 4-6 14 LC6-D46-ES4=40-14-26=0 ES6-D46-ES4=40-14-26=0 ES6-D46-LC4=40-14-26=0 5-6 3 LC6-D56-ES5=40-3-27=10 ES6-D56-ES5=40-3-27=10 ES6-D56-LC5=40-3-37=0 6-7 14 LC7-D67-ES6=54-14-40=0 ES7-D67-ES6=54-14-40=0 Es7-D67-LC6=54-14-40=0 Floats for critical activities are zero
  • 23. • Ex2.A project consist of a series of tasks labelled A to I with the following constraints. • A<D, E ; B,D<F ; C<G;B,D<H;F,G<I; • W<X,Y; means X and Y can’t start until W is completed. You are required to construct a network diagram using this notation. Also find the time of completion of the project ,given the time of completion of each task. Task A B C D E F G H I Time (days) 23 8 20 16 24 18 19 4 10
  • 25. ESj=max(ESi+Dij), forward pass(incoming arrow) Values for early start Latest Completion LCi=min(LCj- Dij) Backward pass(outgoing arrow) Values for latest completion ES1=0 0 LC6=ES6=67 67 ES2=Es1+D12=0+23=23 23 LC5=LC6-D56=67-10=57 57 ES3=max(ES1+D13,ES2+D23) Max(0+8,23+16)=39 39 LC4=LC5-D45=57-19=38 38 ES4=ES1+D14=0+20=20 20 LC3=min(LC5-D35,LC6-D36) Min(57-18,67-4)=39 39 ES5=max(Es3+D35,ES4+D45) Max(39+18,20+19)=57 57 LC2=min(LC3-D23,LC6-D26) Min(39-16,67-24)=23 23 ES6=max(ES2+D26,ES3+D36,ES5+D56) Max(23+24,39+4,57+10)=67 67 LC1=min(LC2-D12,LC3- D13,LC4-D14) Min(23-23,39-8,38-20)=0 0 Critical path conditions: ESi=LCi ESj=LCj ESj-ESi=LCj-LCi=Dij Critical activities 1-2-3-5-6 Duration 23+16+18+10=67 critical
  • 26. • Ex3.Task A to I constitute a project. The notation X<Y means that the task X must be completed before Y is started. • A<D;A<E;B<F;D<F;C<G;C<H;F<I;G<I. Draw a graph to represent the sequence of tasks and find the time of completion of the project, when the time(in days) of completion of each tasks is as follows. Task A B C D E F G H I Time (days) 8 10 8 10 16 17 18 14 9
  • 28. ESj=max(ESi+Dij), forward pass(incoming arrow) Values for early start Latest Completion LCi=min(LCj- Dij) Backward pass(outgoing arrow) Values for latest completion ES1=0 0 LC6=ES6=44 44 ES2=Es1+D12=0+8=8 8 LC5=LC6-D56=44-9=35 35 ES3=max(ES1+D13,ES2+D23) Max(0+10,8+10)=18 18 LC4=min(LC5-D45,LC6-D46) =min(35-18,44-14)=17 17 ES4=ES1+D14=0+8=8 8 LC3=LC5-D35 35-17=18 18 ES5=max(ES3+D35,ES4+D45) Max(18+17,8+18)=35 35 LC2=min(LC3-D23,LC6-D26) Min(44-16,18-10)=8 8 ES6=max(ES2+D26,ES4+D46,ES5+D56) Max(8+16,35+9,8+14)=44 44 LC1=min(LC2-D12,LC3- D13,LC4-D14) Min(8-8,18-10,17-8)=0 0 Critical path conditions: Esi=LCi ESj=LCj ESj-ESi=LCj-LCi=Dij Critical activities 1-2-3-5-6 Duration 8+10+17+9=44
  • 29. • Example 4 .Determine the early start and late start in respect of all node points and identify critical path for the following network.
  • 30. • Solution :Calculation of E and L for each node is shown in the network The critical nodes are (1, 2, 5,7,8,10) There are two possible critical paths i. 1 → 2 → 5 → 8 → 10 ii. 1 → 2 → 5 → 7 → 10
  • 31.
  • 32. PERT FOR DEALING WITH UNCERTAINTY
  • 33. ESTIMATING ACTIVITY TIMES • Optimistic time ( t0 ) : is that time estimate of an activity when everything is assumed to go as per plan. In other words it is the estimate of minimum possible time which an activity takes in completion under ideal conditions. • Most likely time ( tm ) : the time which the activity will take most frequently if repeated number of times. • Pessimistic time ( tp) : the unlikely but possible performance time if whatever could go wrong , goes wrong in series. In other words it is the longest time the can take. • The times are combined statically to develop the expected time te . te = to + 4tm + tp 6 Standard deviation of the time of the time required to complete the project = tp - to 6
  • 34. STEPS INVOLVED IN PERT • Develop list of activities. • A rough network for PERT is drawn. • Events are numbered from left to right. • Time estimates for each activity are obtained. • Expected time for each activity is calculated : to+4tm+tp / 6 • Using these expected times calculate earliest & latest finish & start times of activities. • Estimate the critical path. • Using this estimate compute the probability of meeting a specified completion date by using the standard normal equation Z = Due date – expected date of completion =Ts-Te standard deviation of critical path δ
  • 35. • Example 1:A small project is composed of 7 activities. whose time estimates are listed in the table. Activity 1-2 1-3 2-4 2-5 3-5 4-6 5-6 Estimated duration(we eks) to 1 1 2 1 2 2 3 tm 1 4 2 1 5 5 6 tp 7 7 8 1 14 8 15 a)Draw the project network b) Find the expected duration and variance of each activity c)Calculate the early and late occurences for each event and the expected project length. d) Calculate the variance and standard deviation of project length e)What is the probability that the project will be completed 1.4 weeks earlier than expected. 2.Not more than 4 weeks later than expected. 3.If the project due date is 19 weeks, what is the probability of meeting the date.
  • 36. Activity To tm tp Te=(to+4tm+ tp)/6 Variance 2 =[(tp-to)/6]2 1-2 1 1 7 12/6=2 6/6=(1)2=1 1-3 1 4 7 24/6=4 6/6=1 2-4 2 2 8 18/6=3 6/6=1 2-5 1 1 1 6/6=1 0 3-5 2 5 14 36/6=6 12/6= (2)2 =4 4-6 2 5 8 30/6=5 6/6=1 5-6 3 6 15 42/6=7 12/6=(2)2=4 6 4 5 3 2 1 A(2) B(4) C(3) D(1) E(6) F(5) G(7) ES1=0 LC1=0 ES2=2 LC2=9 ES3=4 LC3=4 ES4=5 LC4=12 ES5=10 LC5=10 ES6=17 LC6=17 ESj=max(ESi+Dij) LCi=min(LCj-Dij)
  • 37. • c)critical path 1-3-5-6,Expected project duration:4+6+7=17weeks Critical activity te Variance2 1-3 4 1 3-5 6 4 5-6 7 4 17 9 Standard deviation(SD)=sqrt(variance) =sqrt(9)=3 d) 1)4 weeks earlier than expected te=17 weeks ts=(17-4)=13weeks p(Z<=D),Where D=(ts-te)/SD D=(13-17)/3=-4/3=-1.33(SNDT) P(Z<D)= .09176=9.17%(out of 100 times 9.1 times, project will be completed 4 weeks earlier than expected) 2)not more than 4 weeks te=17 ts=17+4 SD=3 D=(ts-te)/SD= (21-17)/3=1.33 P(Z<=D)=0.90824=90.82% 3)te=17 ts=19 SD=3 D=19-17/3=0.67 P(Z<=D)=0.7485=74.8%
  • 38. • Ex2: Find the probability of meeting the schedule date as given for the network Activity(i-j) 1-2 1-3 2-4 3-4 4-5 3-5 Optimistic(days) 2 9 5 2 6 8 Most likely(days) 5 12 14 5 6 17 pessimistic(days) 14 15 17 8 12 20 Find the probability that Scheduled project completion date is 30days. Also find the date on which the project manager can complete the project with a probability of 0.90.
  • 39. Activity to tm tp Te=(to+4tm+tp)/6 Variance 2=[(tp-to)/6]2 1-2 2 5 14 36/6=6 12/6=22=4 1-3 9 12 15 72/6=12 6/6=12=1 2-4 5 14 17 78/6=13 12/6=22=4 3-4 2 5 8 30/6=5 6/6=12=1 3-5 8 17 20 96/6=16 12/6=22=4 4-5 6 6 12 42/6=7 6/6=12=1 5 4 3 2 1 A(6) B(12 ) C(13 ) D(5) E(16 ) B(7) ES1=0 LC1=0 ES2=6 LC2=8 ES3=12 LC3=12 ES4=19 LC4=21 ES5=28 LC5=28 Critical path=1-3-5 Expected Project duration=12+16=28 Esj=max(ESi+Dij) and Lci=min(LCj-Dij)
  • 40. activities te Variance2 1-3 12 1 3-5 16 4 28 5 SD=sqrt(5)=2.23 a)Probability of completing in 30 days, te=28 ts=30 SD=2.23 D=(ts-te)/SD=(30-28)/2.23=0.89 P(Z<=D)= .81327=81.32 % b)Given probability=0.90, the number of days required to complete the project. 0.90 from standard normal distribution table =1.29 D=ts-te/SD=1.29 Ts-28/2.23=1.29 Ts=(1.29*2.23)+28 =30.87days
  • 41. • Example 3:Consider the following project, Find the path and standard deviation. Also find the probability of completing the project by 18 weeks. Activity A B C D E F G Predecessor - - A B B C,D E Time estimate(weeks) to 3 2 2 2 1 4 1 tm 6 5 4 3 3 6 5 tp 9 8 6 10 11 8 15
  • 42. 6 5 4 3 2 1 A(6) B(5) C(4) D(4) E(4) F(6) G(6) ES1=0 LC1=0 ES2=6 LC2=6 ES3=5 LC3=6 ES4=10 LC4=10 ES5=9 LC5=10 ES6=16 LC6=16 Activities To(week s) Tm(weeks ) Tp(weeks) Te=(to+4tm+tp)/6 Variance2=[(tp- to)/4]2 A 3 6 9 36/6=6 1 B 2 5 8 30/6=5 1 C 2 4 6 24/6=4 0.44 D 2 3 10 24/6=4 1.77 E 1 3 11 24/6=4 2.77 F 4 6 8 36/6=6 0.44 G 1 5 15 36/6=6 5.44 Esj=max(Esi+Dij) and Lci=min(LCj-Dij) Critical path 1-2-4-6, Expected project duration=16weeks
  • 43. Critical Activities Te for critical activities Variance2 for critical activities A 6 1 C 4 0.44 F 6 0.44 16 1.88 SD=sqrt(Variance2)=sqrt(1.88)=1.374 Probability of completing project by 18 weeks P(Z<=D) D=(ts-te)/SD=18-16/1.374=1.455(check value from normal distribution table) P(Z<=D)=0.92647
  • 44. RESOURCE LEVELLING AND SMOOTHING • Resource optimization is employed when there is a resource conflict (i.e. when the schedule requires more than the available resources) or when there is a need to keep the resource usage at a constant level. • Two examples of resource optimization techniques are: 1. Resource levelling and 2. Resource smoothing • Resource smoothing is used when the time constraint takes priority. The objective is to complete the work by the required date while avoiding peaks and troughs of resource demand. • Resource levelling is used when limits on the availability of resources are dominant.
  • 45.
  • 46. TIME-COST TRADE-OFF • The objective of the time-cost trade-off analysis is to reduce the original project duration, determined form the critical path analysis, to meet a specific deadline, with the least cost. In addition to that it might be necessary to finish the project in a specific time to: • - Finish the project in a predefined deadline date. • - Recover early delays. • - Avoid liquidated damages. • - Free key resources early for other projects. • Avoid adverse weather conditions that might affect productivity. • - Receive an early completion-bonus. • - Improve project cash flow
  • 47. TIME-COST TRADE-OFF CONTD.. • The activity duration can be reduced by one of the following actions: • - Applying multiple-shifts work. • - Working extended hours (over time). • - Offering incentive payments to increase the productivity. • - Working on week ends and holidays. • - Using additional resources. • - Using materials with faster installation methods. • - Using alternate construction methods or sequence. • selecting some activities on the critical path to shorten their duration.
  • 48. HIGHLIGHTS • A project is a unique, one time event of some duration that consumes resources and is designed to achieve an objective in a given time period. • Each project goes through a five-phase life cycle: concept, feasibility study, planning, execution, and termination. • Two network planning techniques are PERT and CPM. Pert uses probabilistic time estimates. CPM uses deterministic time estimates. • Pert and CPM determine the critical path of the project and the estimated completion time. On large projects, software programs are available to identify the critical path.
  • 49. HIGHLIGHTS CON’T • Pert uses probabilistic time estimates to determine the probability that a project will be done by a specific time. • To reduce the length of the project (crashing), we need to know the critical path of the project and the cost of reducing individual activity times. Crashing activities that are not on the critical path typically do not reduce project completion time. • The critical chain approach removes excess safety time from individual activities and creates a project buffer at the end of the critical path.