Business Process Simulation

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Business Process Simulation Marc
Voorhoeve m.voorhoeve_at_tue.nl HG 7.86 (247)2420
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Course structure
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• Aim of the course
• Obtain knowledge and skills w.r.t.
• business process simulation
• whether or not to use simulation
• how to conduct a simulation project
• how to interpret its results

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• Course ingredients
• theory (lecture notes / slides)
• exercises (class / home)
• graded assignments (alleviates exam)
• written exam (open book)

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• Course website //www.win.tue.nl/mvoorhoe/si
  m
• examples
• exercises / assignments

Arena download //campusmp/software/rockwell
downgraded version sufficient for course
examples (not for real simulation projects)
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Prerequisites Modeling with Petri nets - 2V060
Systems modeling (Inf, old) - 2II05 Business
information systems (Inf, new) - 1BB30 Process
modeling (TM) Probability theory and statistics -
2DI25 (Inf) - 2DD13 (TM) Awareness of business
processes - 1CC22 (TM) - common sense
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• Course subjects
• Appropriate use of simulation
• Simulation study outline
• Modeling
• Methodology
• Pitfalls

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Role of Simulation
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Business process
Market trends - quality - quantity - ....
Strategic decisions - infrastructure -
control - ....
feedback
change
influence
influence
Operation characteristics - throughput -
cost - ...
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Strategy adaptation
Trial-and-error approach very wasteful. Before
making an investment, assess its effects (to the
extent possible).
Analysis (probabalistic) calculations
Simulation random generation of cases
measurement
Both depend on parameters, obtained from
historical data, added observations
extrapolations.
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Analysis vs. simulation
History Observations Extrapolation (use with
care)
Analysis - common sense, - stochastic
(markov), - queuing theory - ....
parameters
validate results
validate asssumptions
Simulation
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Simulation project life cycle
Performance indicators of business Challenges,
improvement alternatives Simple analysis,
simulation yes/no?
Problem definition
Essential features of business and proposed
solutions conceptual / executable / parameters
Modeling
Replay history Assessment by stakeholders
Validation
Simulate alternatives parameter sensitivity
Experiment
Interpret
Write report Asess confidence
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Examples
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Passport
A civil servant creates documents for citizens,
who queue for his help. A photo must be attached
to the document, which is judged by the servant.
If the photo is judged inadequate, the citizen is
deferred to a nearby photographer to make a new
one. When the citizen returns with this photo, he
gets priority (without judgement) and his
document is made.
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Ferry
A ferry carries cars across a river. At each
bank, cars can appear needing to cross. When the
ferry is at a bank and is empty, cars can get on
it. There are 10 places for cars at the ferry. If
the ferry is full or if all cars at the current
bank are on board, the ferry crosses to the other
bank, where the cars get off. The cars waiting at
the other bank can then enter the ferry, starting
a new cycle. The current ferry needs replacement
it is at the end of its life cycle, there are
complaints about long waiting times and traffic
is expected to increase. The replacement
candidates are a (faster) one with a capacity of
10 places and a (slower) one with a capacity of
15 places. Find out for both candidate
replacements what the average waiting and
throughput times of cars are for the present
situation and when traffic increases by 10.
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DCT container terminal http//www.youtube.com/watc
h?vsdn8tMgAGOc
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Container Terminal The Dutch Container Terminal
(DCT) is situated in a port. Ships dock at the
terminal, loading and unloading containers. The
containers are temporarily stored in areas at the
DCT premises and moved to and from the shippers
by trucks. Any truck visiting DCT wishes either
to fetch some container (an empty container or a
specific filled container), to bring a container
(empty or filled), or both. The numbers of B and
F trucks are equal in the long run, but F trucks
occur more frequently in the morning and B trucks
in the afternoon.
truck direction
storage areas
keeper
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Containers are moved off and on trucks by a
crane. Before, the driver presents his papers to
the keeper for checking and calculating commands
for the crane. When a truck arrives, it first
queues at the keepers desk. If the papers are
approved, the truck queues for the crane. If not,
the truck is set aside and the driver may try to
set the papers right through telephone and fax.
If this succeeds, the crane queue is entered and
otherwise the truck returns without being
serviced. Trucks in the crane queue wait their
turn then the container either is taken from a B
truck and moved to a storage area or fetched from
the storage area and put on an F truck or the
container is taken from a BF truck and stored,
after which a stored container is put on it.
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Business is increasing. As a consequence, during
busy hours, long truck queues may appear. DCT is
prepared to invest money to improve matters. A
consultancy team of which you are a member is
hired to make suggestions for improvement. Is
simulation an option?
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Classwork / Homework
Classwork Study DCT case. Prepare (in groups) a
list of questions pertaining to the case, discuss
with stakeholder(s) obtain and document answers
Homework Study chapters 1,2 of the lecture
notes. Download Arena. Do the exercises on pages
6 and 10