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Ch. 15 Managing Service Projects
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常見的專案問題
1. 畢專:開學前完成計畫書( Gantt 圖)2. 畢旅,或系學會規劃運管營及交通盃3. 借鏡:訪談本系主辦運輸年會之經驗,老
師提國科會計畫案4. 包括哪些 activity ? Critical path ?
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Learning Objectives
1. the nature of project management (PM)
2. project network and critical path analysis
3. activity crashing: Cost-time Tradeoff
4. incorporating uncertainty in activity times
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1. The Nature of PM
Characteristics purpose, life cycle, interdependencies, uniqueness,
and conflict.
Process planning (work breakdown structure, WBS),
scheduling, and controlling.
Selecting the Project Manager credibility, sensitivity, ability to handle stress, and
leadership.
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1. The Nature of PM
Building the Project Team Forming, Storming, Norming, and Performing.
Principles of Effective PM direct people individually and as a team, reinforce excitement,
keep everyone informed, manage healthy conflict, empower team, encourage risk taking and creativity.
Project Metrics Cost, Time, Performance
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1. PM Questions (4W1H)
What activities are required to complete a project and in what sequence?
When should each activity be scheduled to begin and end?
Which activities are critical to completing the project on time?
What is the probability of meeting the project completion due date?
How should resources be allocated to activities?
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2. Techniques for PM
1. Gantt chart
2. Project network
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2. Tennis Tournament Activities
ID Activity Description Network Immediate Duration Node Predecessor (days)1 Negotiate for Location A - 22 Contact Seeded Players B - 83 Plan Promotion C 1 34 Locate Officials D 3 25 Send RSVP Invitations E 3 106 Sign Player Contracts F 2,3 47 Purchase Balls and Trophies G 4 48 Negotiate Catering H 5,6 19 Prepare Location I 5,7 310 Tournament J 8,9 2
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Notation for Critical Path Analysis
Item Symbol Definition
Activity duration t The expected duration of an activity
Early start ES The earliest time an activity can begin if all previous activities are begun at their earliest times
Early finish EF The earliest time an activity can be completed if it is started at its early start time
Late start LS The latest time an activity can begin without delaying the completion of the project
Late finish LF The latest time an activity can be completed if it is started at its latest start time
Total slack TS The amount of time an activity can be delayed without delaying the completion of the project
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Scheduling Formulas
ES = EFpredecessor (max) (1)
EF = ES + t (2)
LF = LSsuccessor (min) (3)
LS = LF - t (4)
TS = LF - EF (5)
TS = LS - ES (6) or
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Activity on Node Diagram
J2
B8
START
A2 C3 D2 G4
E10 I3
F4 H1
TS ES EF
LS LF
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Early Start Gantt Chart
ID Activity Days Day of Project Schedule 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20A Negotiate for 2 LocationB Contact Seeded 8 PlayersC Plan Promotion 3
D Locate Officials 2
E Send RSVP 10 InvitationsF Sign Player 4 ContractsG Purchase Balls 4 and TrophiesH Negotiate 1 CateringI Prepare Location 3
J Tournament 2
Personnel Required 2 2 2 2 2 3 3 3 3 3 3 2 1 1 1 2 1 1 1 1
Critical Path ActivitiesActivities with Slack
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Resource Leveled Schedule
ID Activity Days Day of Project Schedule 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20A Negotiate for 2 LocationB Contact Seeded 8 PlayersC Plan Promotion 3
D Locate Officials 2
E Send RSVP 10 InvitationsF Sign Player 4 ContractsG Purchase Balls 4 and TrophiesH Negotiate 1 CateringI Prepare Location 3
J Tournament 2
Personnel Required 2 2 2 2 2 2 2 2 2 2 2 2 2 3 2 2 2 2 1 1
Critical Path ActivitiesActivities with Slack
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3. Costs for Hypothetical Project
Cos
t
(0,0)
Schedule with Minimum Total Cost
Duration of Project
Total Cost
Indirect Cost
Opportunity Cost
Direct Cost
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Cost-Time Estimates
Time Estimate Direct Cost Expedite CostActivity Normal Crash Normal Crash Slope A 2 1 5 15 10 B 8 6 22 30 4 C 3 2 10 13 3 D 2 1 11 17 6 E 10 6 20 40 5 F 4 3 8 15 7 G 4 3 9 10 1 H 1 1 10 10 - I 3 2 8 10 2 J 2 1 12 20 8 Total 115
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Activity Cost-time Tradeoff
C
C*
D* D Activity Duration (Days)
Normal
CrashSlope is cost to expedite per day
Cost
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Progressive Crashing
Project Activity Direct Indirect Opportunity TotalDuration Crashed Cost Cost Cost Cost 20 Normal 115 45 8 168 19 41 6 18 37 4 17 33 2 16 29 0 15 25 -2 14 21 -4 13 17 -6 12 13 -8
Normal Duration After Crashing ActivityProject Paths DurationA-C-D-G-I-J 16A-C-E-I-J 20A-C-E-H-J 18A-C-F-H-J 12B-F-H-J 15
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4. Incorporating Uncertainty in Activity times
A M D B
F(D)P(D<A) = .01
P(D>B) = .01
optimistic most pessimistic likely
TIME
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Formulas for Beta Distribution of Activity Duration
1. Expected Duration
DA M B_
4
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2. Variance
VB A
6
2
Note: (B - A )= Range or 6
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Activity Means and Variances
Activity A M B D V A 1 2 3 B 5 8 11 C 2 3 4 D 1 2 3 E 6 9 18 F 2 4 6 G 1 3 11 H 1 1 1 I 2 2 8 J 2 2 2
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Uncertainly Analysis
Assumptions1. Use of Beta Distribution and Formulas For D and V2. Activities Statistically Independent3. Central Limit Theorem Applies ( Use “student t” if less than 30 activities on CP) 4. Use of Critical Path Activities Leading Into Event Node
ResultProject Completion Time Distribution is Normal With:
For Critical Path Activities
For Critical Path Activities
D_
2 V
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Completion Time Distribution
Critical Path Activities D V A 2 4/36 C 3 4/36 E 10 144/36 I 3 36/36 J 2 0
= 20 188/36 = 5.2 = 2
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Question
What is the probability of an overrun if a 24 day completion time is promised?
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P (Time > 24) = .5 - .4599 = .04 or 4%
Days
2 5 2 .
ZX
Z
Z
24 20
52175
..
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Discussion: Applying Theory of Constraints (TOC) to PM
Why does activity safety time exist and is subsequently lost?1. The “student syndrome” procrastination phenomena.2. Multi-tasking muddles priorities.3. Dependencies between activities cause delays to accumulate.
Buffer: Reduce by ½ all activity durations > 3 days to eliminate safety time
Software: Project 2000
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Exercise
Prepare a work breakdown structure (WBS) for a homecoming dance.