Professor Stewart Robinson Stewart Robinson Loughborough University 1 Sessio n Outline What is simulation Why use simulation Four simulation approaches Stewart Robinson Loughborough University ID: 656785
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Slide1
Introduction to Simulation Methods
Professor Stewart Robinson
Stewart Robinson
Loughborough University
1Slide2
Session Outline
What is simulation?
Why use simulation?Four simulation approaches
Stewart Robinson
Loughborough University
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Loughborough University
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How did British Airways Decide on the Design of Terminal 5?
How many check-in desks?
How many departure gates?
Configuration of security screening
Design of baggage handling system
Size of passport control area?
Flight schedule capacity
Workforce rostersSlide4
Terminal 5 Simulation
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Loughborough University
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Source: Beck, A. (2011). Journal of Simulation 5, 69–76Slide5
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Loughborough University
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What is Simulation?
Experimentation with a simplified imitation (on a computer) of a ... system as it progresses through time, for the purpose of better understanding and/or improving that system.
(Robinson,
2014
)
Simulation is: an
imitation
of a system
Simulation videoSlide6
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Loughborough University
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What is Simulation?
A simulation model enables a manager to experiment with alternative courses of action, the simulation providing predictions about the likely outcome. As a result, the manager obtains a better understanding of reality and is able to identify ‘good’ courses of action.
Simulation
model
Inputs
Outputs
ExperimentationSlide7
Examples of SimulationFord Motor Company
. Simulation was widely used to aid the planning and design of their Zetec engine plants in South Wales. These represented an investment of $750m.
The simulations helped improve output by around 30%.
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Loughborough University
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Examples of SimulationEmptying a waste pond and processing the waste to make it safe.
Achievement of waste removal to a specified timeline.
Nuclear Industry
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Loughborough University
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Examples of SimulationOutpatients Department Rebuild
: investigation of number of consulting rooms required.
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Loughborough University
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Why Use Simulation?Because systems are subject to
variability, are interconnected
and complex.1. Variability:Predictable variability e.g. shift changeovers, preventative maintenanceUnpredictable variability e.g. customer arrivals, breakdown
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Loughborough University
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Why Use Simulation?2. Interconnectedness
Variability does not occur in isolation, but is connected to other sources of variability.
Service 1Service 2Service 3
CustomerarrivalsTime: 10 minsTime: 9 mins
Time: 9 mins
Time: 9 mins
What is the mean time a customer spends in the system?
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Loughborough University
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Why Use Simulation?3. Complexity
Combinatorial complexity: the number of combinations of system components that are possible.
20 interconnections
2 interconnections
Combinatorial complexity
is related to the size of a system.
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Loughborough University
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Why Use Simulation?3. Complexity
Dynamic complexity: related to the interaction of components in a system over time.
It is normally associated with feedback e.g. a kanban system:
M1B1Parts
Information
It is not necessarily related to the size of a system.
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Loughborough University
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Simulation Approaches
Monte Carlo Simulation (not strictly business dynamics)
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Loughborough University
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f (a, b, c)
Random sampling process (hence ‘Monte Carlo’)
Not always dynamic (time-based) models
Typical used in finance applications for portfolio managementSlide15
Simulation Approaches
Discrete-Event Simulation
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Loughborough University
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World represented as Queues and Activities
Variable time step to represent changes in state of the system
Used for modelling queuing systems e.g. airports, banks, manufacturing plant, call centres, ports, computer systems,...Slide16
Simulation Approaches
Continuous Simulation (e.g. system dynamics)
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Loughborough University
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World represented by Stocks and Flows
Constant (small) time step (
Δ
t
) to approximate continuous time
Typical used in business strategy/policy and more general continuous simulation in science and engineeringSlide17
Simulation Approaches
Agent Based Simulation
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Loughborough University
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World represented by (intelligent) interacting agents
Constant time step (
Δ
t
) but can be discrete-event
Used for exploring emergent behaviour in organisations as well as other
contexts: e
vacuation
, traffic
flow, stock markets, diffusion
of
innovation, spread of infectious diseases
Boids simulationSlide18
Reading
Discrete-Event Simulation
Robinson, S. (2014). Simulation: The Practice of Model Development and Use, 2nd ed. Palgrave, London. Law, A.M. (2014). Simulation Modeling and Analysis, 5th ed
. McGraw-Hill, New York. System Dynamics Morecroft, J. (2007). Strategic Modelling and Business Dynamics: A Feedback Systems Approach. Wiley, Chichester. Sterman, J.D. (2000).
Business Dynamics: Systems Thinking and
Modeling
for a Complex World
. McGraw-Hill, New York.
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Loughborough University
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Reading
Agent Based Modelling
Robertson, D.A. and Caldart, A.A. (2009). The Dynamics of Strategy: Mastering Strategic Landscapes of the Firm. Oxford University Press. Axelrod, R. (1997). The Complexity of Cooperation: Agent-Based Models of Competition and Collaboration
. Princeton University Press. North, M.J. and Macal, C.M. (2007). Managing Business Complexity: Discovering Strategic Solutions with Agent-Based Modeling and Simulation. Oxford University Press.
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Loughborough University
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