Dynamic system modeling

Question 1

What is system thinking?

Answer 1

Any process of estimating or inferring how local policies, actions, or changes influences the state of the neighboring universe

Question 2

What is the advantage of system thinking?

Answer 2

• Allow to estimate the system behavior over time
• Concerning multi-criteria objectives;
• Integrating all necessary qualitative and quantitative variables and relations;
• Enabling dynamic systems modeling with non-linear effects and causal-loop-
• feedbacks.
• Make it possible to asses the various effects of decision taking in land-use and
• transport related policies.

Question 3

What is the limitation of system thinking?

Answer 3

• No integration of spatial dynamics. On a regional scale, spatial dynamics have to be integrated. It seems to be possible to link system dynamic to geographical information systems or to implement fine spatial zoning in system dynamics environment.
• The challenge is to integrate causal loop interactions with individual choice behavior defining agents that process decisions on the structural basis (multi-agent modeling).

Question 4

How can system thinking models contribute to represent quantitative and qualitative interaction?

Answer 4

Sensitivity model: Working out an integrated model scheme, defining specific scenarios for (qualitative) simulation
System Dynamics: Impact estimation for specific questions: Testing different policies and measures by (- more or less - quantitative) simulation

Question 5

Is it possible to differentiate between the potential of urban qualities and the behavior of actors (individuals, household…)?

Answer 5

JMMM

Question 6

The process of sensitivity model

Answer 6

1) System description
• Defining the topics/scope/research questions
• Setting the system boundary
• Making the system element
2) Set of variables
• Define system elements
• Directional, qualitative fuzzy scales
3) Criteria matrix: Test the relevance for global system (economy…)
4) Impact matrix: Evaluation the strength of influence between each variable.
5) Systemic role: Cybernetic role of the variables in the system
6) Effect analysis: identifying feedbacks analysis and cause-and-effect loops (Reinforce impact or counteracting impact)

7) Partial scenarios: visualizing detailed functions
8) Simulation
9) System Evaluation: following the eight rules of biocyrbernastics

Question 7

What is the central rule of biocyrbernastic?

Answer 7

Negative feedback should be dominated over positive feedback
Self-regulation In a sustainable system balancing (negative) feedback loops must outweigh reinforcing (positive) feedback loops

Question 8

Working principle of system dynamic, and the difference from sensitivity model

Answer 8

What makes using system dynamics different from other approaches to studying complex systems is the use of feedback loops and stocks and flows. These elements help describe how even seemingly simple systems display baffling nonlinearity.
• qualitative interaction -> Sensitivity model
• quantitative interaction -> Dynamic System Thinking

Question 9

What are pros and cons of sensitivity model

Answer 9

Pros
• Clear and useful structure for model development
• Qualitative variables and functional relations by table functions can be elaborated transparently.

Cons
•	Time consuming 
•	Restricted simulation. Simulation of 
parts of the whole system only. 
•	No quantitative results 
•	No spatial dynamics.

Question 10

What are pros and cons of System dynamics

Answer 10

Pros
Open environment for software development
Development of model structure is fast

Cons
• Insufficient structuring of the development process.
• Filling the functions, testing and calibrating takes time
• Restricted system analysis tools, Transparency and communication are difficult.
• No spatial dynamics