Applied Management Science
Introduction
Tran, Van Hoai
Faculty of Computer Science & Engineering
HCMC University of Technology
2012-2013
Tran Van Hoai
1
Jam jam jam
2012-2013
Tran Van Hoai
2
…and still jam jam jam
2012-2013
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3
Ideas ?
Beginning of human-beings
• General solutions
– to remove network of roads
– to …destroy all vehicles
– to open more roads
LONG TERM
• to extend existing roads
– To reduce vehicles (or people)
• To extend existing vehicles’ size
HCMC, Hanoi
2010-2011
Tran Van Hoai
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Ideas
• Operational solutions
Road(s)
– to modify intersection geometry
Control(s)
– to control traffic light(s)
SHORT TERM
• static, dynamic (adaptive)
– to assign lanes for each vehicle type
• routes assigned for each lane
Vehicle(s)
– to enforce law/regulations on drivers
2010-2011
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Challenge in proposed solutions
SCIENTIFIC APPROACH
Modeling
Analyzing
Simulating
Optimizing
QUANTITATIVE RESULT
• Ideas to solve traffic jam are quite obvious
• But how to solve is not easy
2010-2011
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Definitions
• Management science is the discipline that adapts the
scientific approach for problem solving to executive
decision making in order to accomplish the goal of
“doing the best you can with what you’ve got”
(Laurence & Pasternack)
• Operations research is an interdisciplinary branch of
applied mathematics and formal science using
mathematical modeling, statistical analysis, and
mathematical optimization, … to arrive at optimal or
near-optimal solutions to complex decision-making
problems
(wiki)
2010-2011
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More (historical) definitions
• Scientific methods of providing executive departments
with a quantitative basis for decisions regarding
operations under their control
(Morse & Kimball – 1951)
• The use of techniques such as statistical inference and
decision
theory,
mathematical
programming,
probabilistic models, network and computer science [to
solve complex operational and strategic issues]
(US Army Pamphlet 600-3)
2010-2011
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Who need MS/OR ? (1)
• Profit company
– To make money for stockholders
– To subject to responsibilities/restrictions
•
•
•
•
2010-2011
Delivering in reasonable time
Fair wage/working conditions for workers
Good products/services
…
Tran Van Hoai
Doing
the
best
with
what
you’ve
got
9
Who need MS/OR ? (2)
• Nonprofit organization
– To provide minimum cost
– To subject to responsibilities/restrictions
• Being responsible to oversees (donors,
subscribers,…)
• Good service
•…
2010-2011
Tran Van Hoai
Doing
the
best
with
what
you’ve
got
10
Who need MS/OR ? (3)
• Government agencies
– To expect citizens,company to obey laws
– To subject to responsibilities/restrictions
• Limitation of resources (capital, personnel,
technology,…)
•…
2010-2011
Tran Van Hoai
Doing
the
best
with
what
you’ve
got
11
Who need MS/OR ? (4)
• My wife:
to choose among n foods, each provides some
Doing
of each of m nutrients
– To find least expensive diet
– To subject to responsibilities/restrictions
• Guaranteeing nutrients totally provided
•…
2010-2011
Tran Van Hoai
the
best
with
what
you’ve
got
12
Some applications
(not in Vietnam)
• Producing Hamburgers at Burger King
– Linear programming
• Scheduling Crews at American Airlines
– Integer linear programming
• Planning the Sony Advanced Traveler Information System
– Shortest path network
• Planning Environmental Policy in Finland
– Decision analysis
• Cooking at Mrs. Fields
– Inventory modeling
• Designing Attractions at Disneyland
– Queuing models
• Transporting Trash in New York City
– Simulation model
2010-2011
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What is crew scheduling ?
SGN
HAN
HAN
DAD
DAD
SGN
0730
0940
1340
1455
1655
1810
Aircraft 1
HAN
SGN
SGN
DAD
DAD
HAN
1010
1215
1510
1625
1650
1800
Aircraft 2
-To assign pilots to flight legs
-To manage pilot database, including
 Personal information
 Timetable for training, vacation, day-off, …
-To monitor/report daily operations
Trivial schedule
SGN
A
HAN
HAN A DAD
DAD A SGN
0940
1340
1655
Aircraft 1
0730
Aircraft 2
1455
HAN B SGN
SGN
1010
1510
1215
B
1810
DAD
DAD B HAN
1625
1650
1800
- Easy to make manually, but
 Having critical drawbacks …
(pilot A) 4h + 2h + (pilot B) 2h55' + 25'
= 9h20' idle for duty/ground out-base
Better schedule
PrimeSolution schedule
SGN
A
HAN
HAN B DAD
DAD A SGN
0940
1340
1655
Aircraft 1
0730
Aircraft 2
1455
HAN A SGN
SGN
1010
1510
1215
A
1810
DAD
DAD B HAN
1625
1650
1800
- Much less duty/ground out-base time
 Less payment for idle time
 Backup pilots for disruptions
(pilot A) 30' + 30' + (pilot B) 1h55'
= 2h55' idle for duty/ground out-base
and MS/OR has more
PrimeSolution fulfillment of rules
SGN
A
HAN
HAN A DAD
DAD A SGN
0940
1340
1655
Aircraft 1
0730
Aircraft 2
1455
1810
HAN B SGN
SGN
B
1010
1510
violates
1215
DAD
1625
DAD B HAN
1650
1800
Do not allow connection with rest
time less than 30'
SGN
A
HAN
HAN B DAD
DAD A SGN
0940
1340
1655
Aircraft 1
0730
Aircraft 2
1455
HAN A SGN
SGN
1010
1510
1215
A
1810
DAD
DAD B HAN
1625
1650
1800
Key challenges – rules
 Must comply with sets of rules
– Issued by the government
(Cục hàng không dân dụng)
- Number of flying time per day
- Number of duty time per week
- Minimum resting time between consecutive flights
- Minimum resting time for a week, month, year
-…
– Union/Contractual agreements
– Operational rules
- Maximum number of consecutive flights out-base
- Maximum days for consecutive flights out-base
- Bases for night resting
-…
COMPLEX
- Cannot check manually
- Often changed
Key challenges – cost structures
 Crew cost only less than fuel cost
– Payment for crew flying time
– Payment for duty/ground out-base time
- Hotel costs
- Per diem expenses
- Dead-heading cost
-…
– Operational objectives
- Maximize number of patterns (tour-of-duty)
- Minimize number of patterns
- Minimize number of out-base night rests
-…
TRADEOFF
SPECIFIC
- Non-expert cannot model
- Often changed
Key challenges – number of solutions
 Business view point
– Find low cost/high profit solution, but
do not violate any rules
- Good solution but violating rules
- Valid solution but high cost
-…
 Operational view point
– Find robust (for disruption)
solution, but do not violate rules
- Robust solution but violating rules
- Valid solution but weak
-…
HUGE #
HARD
- Manual schedule is impossible
- Only information technology
and mathematics can help
Current schedule
Possible rule violation
61 duty/ground out-base nights
MS/OR provides better schedule
A better schedule
No rule violation
35 duty/ground out-base nights
History
• Reading materials (given later)
• Similar words:
– Operation research
– Management science
– Decision sciences
– Quantitative methods
• Take (often) a quantitative view of decision making
– Industrial engineering
2010-2011
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MS/OR process
Problem Definition
Mathematical Modeling
Solution of the Model
Communication/Implementation of Results
2010-2011
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