l8 - project management - (part 2) (1)

7/25/2019 L8 - Project Management - (Part 2) (1)

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Operations Management

(MT201)Dr. Marty Reilly

[email protected]

Office hours Room !11"

#ednesday 11am $ 12

Thursday 11am $ 12


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TopicsPlanning & Control:

Project Management (part 2)

%ntroduction

&tages in 'ro ect Management

#or *rea do+n &tructuresProject Scheduling*

PERT & CPM

Project Crashing


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,antt -hartsThe ,antt chart pro ides an o er ie+ for the 'ro ect Manager to allo+ them tomonitor pro ect progress against planned progress and so pro ides a alua/leinformation source for pro ect control.


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et+or techni ues

De eloped in 1 304s-'M /y Du'ont for chemical plants (1 35)

'6RT /y *oo78 9llen : ;amilton +ith the


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&i> &teps '6RT : -'M

1. Define the pro ect and prepare the +or /rea do+n structure

2. De elop relationships among the acti ities $ decide +hich acti itiesmust precede and +hich must follo+ others

?. Dra+ the net+or connecting all of the acti ities

". 9ssign time and or cost estimates to each acti ity

3. -ompute the longest time path through the net+or A this is called the

critical pathB.


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1. #hen +ill the entire pro ect /e completedC

2. #hat are the critical acti ities or tas s in the pro ectC?. #hich are the noncritical acti itiesC". #hat is the pro/a/ility the pro ect +ill /e completed /y a specific

dateC3. %s the pro ect on schedule8 /ehind schedule8 or ahead of scheduleC

B. %s the money spent e ual to8 less than8 or greater than the /udgetC5. 9re there enough resources a aila/le to finish the pro ect on timeC=. %f the pro ect must /e finished in a shorter time8 +hat is the +ay to

accomplish this at least costC

!uestions '6RT : -'M can 9ns+er


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9O (9cti ity on ode) 6>ample

Activity Description ImmePredece A Build internal components

B Modify roof and floor

C Construct collection stack A

D Pour concrete and install frame A, B

E Build high temperature !urner C

" Install pollution control system C

# Install air pollution device D, E

$ Inspect and test ", #

Paper Manufacturing Plant DevelopmentActivities and Predecessors


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'erform a -ritical 'ath 9nalysisDetermines project duration

The critical path is the longest path through the net+or

The critical path is the shortest time in +hich thepro ect can /e completed

9ny delay in critical path acti ities delays the pro ect

-ritical path acti ities ha e no slac time


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'erform a -ritical 'ath 9nalysis6>ample of a ne+ 'aper 'lant

9cti ity Description Time (+ee s)9 *uild internal components 2* Modify roof and floor ?- -onstruct collection stac 2D 'our concrete and install frame "6 *uild high$temperature /urner "

%nstall pollution control system ?, %nstall air pollution de ice 3; %nspect and test 2

Total Time (+ee s) 23


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Determining the 'ro ect &chedule -ritical 'ath 9nalysis

Earliest start (ES) E earliest time at +hich an acti itcan start8 assuming all predecessors ha/een completed

Earliest finish (EF) E earliest time at +hich anacti ity can /e finished

Latest start (LS) E latest time at +hich an acti itycan start so as to not delay the completion time of theentire pro ect

Latest finish (LF) Elatest time /y +hich an acti ityhas to /e finished so as to not delay the completiontime of the entire pro ect


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'erforming a -ritical 'ath 9nalysis eedto use a legend

9

9cti ity ame or &ym/ol

6arliest &tart6&

6arliest in6

Fatest &tart F& Fatest iniF

9cti ity Duration

2


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or+ard 'ass

*egin at starting e ent and +or for+ardG

Earliest Start Time ule:%f an acti ity has only a single immediate predecessor8 its 6&e uals the 6 of the predecessor

%f an acti ity has multiple immediate predecessors8 its 6& is thema>imum of all the 6 alues of its predecessors

Earliest Finish Time ule:The earliest finish time (6 ) of an acti ity is the sum of itsearliest start time (6&) and its acti ity time


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6& 6 et+or for 'aper 'lant

&tart

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6 E 6& H 9cti ity time


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Latest Finish Time ule:%f an acti ity is an immediate predecessor for ust a singleacti ity8 its F e uals the F& of the acti ity that immediatelyfollo+s it%f an acti ity is an immediate predecessor to more than one

acti ity8 its F is the minimum of all F& alues of all acti itiesthat immediately follo+ it

*ac +ard 'ass (we need this to determine slac times later)

!egin with the last e"ent and wor #ac wards

Latest Start Time ule:

The latest start time (F&) of an acti ity is the difference of its latestfinish time (F ) and its acti ity time eg8 (F& E F A 9cti ity time)


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F& E F A 9cti ity time

F& F Times for 'aper 'lant


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F E Min(F& of follo+ing acti ity)

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9fter computing the 6&8 6 8 F&8 and F times for all acti ities8

compute the slac or free time for each acti ity

&lac is the length of time an acti ity can /e delayed +ithoutdelaying the entire pro ect

&lac E F& A 6& or &lac E F A 6

-omputing &lac Time


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6arliest 6arliest Fatest Fatest On

&tart inish &tart inish &lac -ritical9cti ity 6& 6 F& F F& A 6& 'ath

9 0 2 0 2 0 Ies* 0 ? 1 " 1 o- 2 " 2 " 0 IesD ? 5 " = 1 o6 " = " = 0 Ies

" 5 10 1? B o, = 1? = 1? 0 Ies; 1? 13 1? 13 0 Ies

-omputing &lac Time

Critical path is: !"C"E"#"$


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-ritical 'ath for 'aper 'lant


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1. 6specially useful +hen scheduling and controlling large pro ects

2. &traightfor+ard concept and not mathematically comple>?. ,raphical net+or s help highlight relationships among pro ect

acti ities

". -ritical path and slac time analyses help pinpoint acti ities thatneed to /e closely +atched

3. 'ro ect documentation and graphics can point out +ho is responsi/lefor arious acti ities

B. 9pplica/le to a +ide ariety of pro ects

5.


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;o+ does '6RT : -'M differC

'6RT is ery similar to -ritical 'ath Method (-'M) /ut also uses

three time estimates for each acti ity

%ptimistic Time shortest duration li ely

'ost Li el Time a erage e>pectation

Pessimistic Time the most conser ati e estimate8 ta inginto account the li elihood of set/ac s etc

2=


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1. 'ro ect acti ities ha e to /e clearly defined8 independent8 and sta/lein their relationshipsG not alwa$s a realit$

2. 'recedence relationships must /e specified and net+or ed together

?. Time estimates tend to /e su/ ecti e and are su/ ect to Jfudging4 /ymanagersG were estimates su#jecti"e % too optimistic

". There is an inherent danger of too much emphasis /eing placed onthe longest8 or critical8 pathG. *near+ critical paths should also ,emonitored closel -

Fimitations Disad antages of '6RT -'M


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The pro ect is /ehind scheduleThe completion time has /een mo ed for+ard

'a incur penalties if the project runs o.er late-/

%t is not uncommon to face the follo+ingsituations

&hortening the duration of the pro ect is called project crashing

Trade$Offs 9nd 'ro ect -rashing

For e0ample1 if 2e need an acti.it done 3uic er can 2eemplo e0tra staff1 or pa e0isting staff o.ertime in order toachie.e this4

d h h


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The amount /y +hich an acti ity is to /e crashed is8 in fact8 permissi/le

Ta en together8 +ill the shortened acti ity durations ena/le us to finishthe pro ect /y the due dateC

Or ha e +e ust increased our spending +ithout achie ing completion/y the due dateC

eed to ensure that the total cost of crashing is as small as possi/le

actors to -onsider #hen -rashing 9 'ro ect

l8 - project management - (part 2) (1)

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