Tobias Deutsch Simulation - Institut für Computertechnik

KuKi
Simulation
384.112 VU 2.0
Simulation
AK der Kognitionswissenschaft und
Künstlichen Intelligenz
Institut für
Computertechnik
ICT
Tobias Deutsch
Institute of
Computer Technology
Simulation
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Simulation
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Types of Simulation
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Predictability
Time model
Locality
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Agent Based Simulation
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Bubble Family Game
Institut für Computertechnik
KuKI: Ausgewählte Kapitel Kognitionswissenschaft
& Künstliche Intelligenz
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Computer Simulation Definitions
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The process of imitating a real phenomenon with a set
of mathematical formulas.
http://www.webopedia.com
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Simulation ist die Nachbildung eines dynamischen
Prozesses in einem realen Modell, um zu Erkenntnissen
zu gelangen, die auf die Wirklichkeit übertragbar sind.
DIN 3633
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A computer simulation or a computer model is a
computer program which attempts to simulate an
abstract model of a particular system.
http://en.wikipedia.org/wiki/Computer_simulation
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KuKi
Simulation
Why Simulate
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Closed form analytic solutions not possible
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Real world experiments not possible
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Target system does not exist (yet)
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Prove a theory in controlled environment
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Etc.
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Simulation Cycle
F.Breitenecker TU Wien
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Simulation Modeling Steps
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Problem formulation
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Modeling / Degree of abstraction
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Analysis of model
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Verification of model
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If verification against problem formulation fails, back to
Modeling
Experiments with the model
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Simulation
Optimization Experiments
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For verified models
Find the best parameters for a desired
simulation outcome
Parameters can be ranged to reduce search
range
Monte Carlo methods for selecting paramters
Function for desired outcome difficult to define
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Can’t do miracles!
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Institut für Computertechnik
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The 10 DON’Ts of Mathematical Modeling
1. Don't believe in the 33rd order consequences of a 1st order model.
2. Don't extrapolate beyond the region of fit.
'Cum grano salis.‘
'Don't go off the deep end.'
3. Don't apply any model until you understand the simplifying assumptions on which it is
based, and can test their ability.
'Use only as directed.'
4. Don't believe the model is reality.
'Don't eat the menu.'
5. Don't distort reality to fit the model.
'The Procrustes Method.'
6. Don't limit Yourself to a single model: More than one may be useful for
understanding different aspects of the same phenomenon.
'Legalize polygamy.'
7. Don't retain a discredited model.
'Don't beat a dead horse.'
8. Don't fall in love with your model.
'Pygmalion.'
9. Don't apply terminology of subject A to the problems of subject B if it is to the
enrichment of neither.
'New names for old.'
10. Don't expect by having named a demon you have destroyed him.
'Rumpelstiltskin.'
Golomb, S.W., 1970. Mathematical Models - Uses and Limitations. Simulation, 4 (14), 197-198.
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The 10 DON’Ts of Mathematical Modeling
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Don't believe the model is reality.
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Don't distort reality to fit the model.
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Don't extrapolate beyond the region of fit.
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Don't retain a discredited model.
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Don't fall in love with your model.
Golomb, S.W., 1970. Mathematical Models - Uses and Limitations. Simulation, 4 (14), 197-198.
Institut für Computertechnik
KuKI: Ausgewählte Kapitel Kognitionswissenschaft
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KuKi
Simulation
Types of Simulation
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Locality
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Predictability
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Local vs.
Distributed
Stochastic vs.
Deterministic
Time model
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Continuous vs.
Discrete
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Predictability
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Stochastic
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Usage of random number generators
Also called Monte Carlo simulations
Real life processes
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Client arrivals, device failures, people decisions, …
Deterministic
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Reproducible results
Perform always the same for a given input
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Time Models - Continuous
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Values change with time
Differential equations (partly or ordinary)
Implemented numerically
Continuous trajectories are obtained in discrete
time steps
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Simulation
Time Models - Discrete
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Event based
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Causes changes in the state
Takes zero time
Simultaneous events are
serialized (random or
deterministic order)
Types of Events
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Timer (static or dynamic)
State transisitions
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Time Models - Hybrid
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Hybrid
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Combination of continuous and discrete time models
E.g. event injection
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Institut für Computertechnik
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Agent Based Simulation
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Special case of discrete time models
No underlying equation
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The model …
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is represented directly
has an internal state
a set of rules/behaviors
Institut für Computertechnik
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Simulation
What is an Agent
Agent
*) Attributes
*) Behavioral rules
*) Memory
*) Ressources
*) Decision making
sophistication
*) Rules to modify
behavioral rules
Environment
and
Agents
Macal, C. and North, M., 2005, Tutorial on Agent-Based Modeling
and Simulation, Proceedings of the 2005 Winter Simulation Conference
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Agent Based Simulation
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Agents are individuals
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Interact with each others
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Simple rules may lead to complex simulations (e.g.
Flock of Boids http://www.red3d.com/cwr/boids/index.html)
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Spatial distribution easy to simulate
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KuKI: Ausgewählte Kapitel Kognitionswissenschaft
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Agent Based Simulation Applications
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Business and Organizations
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Economics
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Manufacturing, consumer markets, supply chains, insurance
Artificial financial markets, trade networks
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Infrastructure
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Crowds
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Human movement, evacuation modeling, spread of diseases
Society and Cultures
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Electric power markets, hydrogen economy, transportation
Ancient civilizations, civil disobedience, social interaction, psychology
Terrorism
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Social determinants, organizational networks
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Military
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Biology
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Command & control, Force-on-force
Ecology, Animal group behavior, Cell behavior, Sub cellular molecular behavior
Macal, C. and North, M., 2005, Tutorial on Agent-Based Modeling
and Simulation, Proceedings of the 2005 Winter Simulation Conference
Institut für Computertechnik
KuKI: Ausgewählte Kapitel Kognitionswissenschaft
& Künstliche Intelligenz
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KuKi
Simulation
Hare Rising Stories
Continuous Model
Agent Based Model
online resource
online resource
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KuKI: Ausgewählte Kapitel Kognitionswissenschaft
& Künstliche Intelligenz
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Crowd Simulation
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Institut für Computertechnik
online resource / www.xjtek.com
KuKI: Ausgewählte Kapitel Kognitionswissenschaft
& Künstliche Intelligenz
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Bubble Family Game
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Bubbles are autonomous
agents
Organized in teams
Need energy to survive
Every action costs energy
Energysources provide
energy
Bubble
Energysource
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KuKi
Simulation
Are You Living In a Computer Simulation?
Bostrom, Nick, (2003), Are You
Living In a Computer Simulation?,
There are more things in heaven
and earth, Horatio, than are dreamt
of in your philosophy
Philosophical Quarterly, 2003, Vol.
53, No. 211, pp. 243-255.
Hamlet (I, v, 166-167)
http://www.simulation-argument.com/
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Welt am Draht (1973)
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Movie by Rainer Werner Fassbinder
Based upon the book
Simulacron-3 by Daniel F. Galouye
A simulated world inside the simulated
world
Test effects of a perfect simulation on
society
Personalities start to “diffuse” to other
levels
(Forget about “The Matrix”)
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& Künstliche Intelligenz
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