Spreading System Dynamics to
SMEs by using Generic Structures
Katrin Hügel, Lukas Schmid & Marcel Loher
Lisbon, 13. July 2010
24th European Conference on Operational Research
1
Generic Models – Overview
Canonical situation
model
Self-contained
models
Transfer accross
fields
General Insights
system archtypes
Case specific solutions
Transfer within
particular field
solve individual
problem
assembled models
(LEGO)
abstracted micro
structures
„Rather than stressing the single-model concept, it appears that we should
stress the process of modeling as a continuing companion to, and tool for,
the improvement of judgement and human decision making“
[ Forrester in System Dynamics Review Vol.1, No.1 1985]
2
Generic Models – pro & contra
Validation
3
Validation – Experiences with SME
model structure
Structure verification
Experts SME
Parameter verification
Availability of data
Extreme conditions
Experts SME, experience?
Boundary Adequacy
Availability of data
Dimensional consistency
model behaviour
policy implications
[core tests Forrester/ Senge, 1980]
done by modellers

Behavior reproduction
Availability of data
Behavior Anomaly
Completeness?!
Behavior Sensitivity
Completeness?!
Changed behavior prediction
Experts SME
Policy sensitivity
Experts SME
4
Benefits expected from Generic Models
• Main structures of the model will be validated in general
• Every user contributes testing: approves confidence or improves the
model by modifications
• Research on details contributes to the greater model
• Higher comparability of findings facilitates scientific discourse
• Acceptence of models by scientific proof
• Facilitates implementation of new findings in practical use
?
FEASEBILITY
5
Example from Engineering: Activated Sludge Process
6
Activated Sludge Models: Development
various modelling approaches
1982
International Organisation Water Polution Research & Controll
established a Task Group on Mathematical Modelling for Design
and Operation of activated sludge processes
1987
Activated Sludge Model (ASM) No.1 published
1995
ASM No. 2 published, containing an additional process
(biological phosphorus removal)
1999
ASM No. 3 published, revised version of ASM1
2005
Additional Task Group on Good Modelling Practice (GMP),
takes care for approriate use of ASM in professional life
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Activated Sludge Model 3:
Tab1. Stoichiometric matrix and composition matrix of ASM3
Tab2. Kinetic rate expressions of ASM3
Tab 3. Typical values of kinetic parameters (21 parameters provided as examples)
Tab 4. Typical stoichiometric and composition parameters (15 parameters provided as examples)
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Conclusiones & Prospects
•
several findings argue for feasebility of generic models
• generic modeling does not conpromise focus on modeling process
• high expectations justify time and effort
• solve problems, compromising SD application in real life
• enhence effectiveness & efficiency of research
• enables discourse between research and real life application
Preconditions:
•
Lead organisation equally interested in research and practical
implementation of models
• Task group consisting of respectable researchers
• Realistic expectations considering time table (5-15 a) and value of the model
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