A quick introduction to System Dynamics Simulation using Vensim.

1. MODELING WITH VENSIM 101:
BASICS

2. First: System dynamics…
How is my inventory
policy affecting my
cash flow? Is an ERP the
‘answer’ to our
problems?
How can people
respond to a tax
increment?
It’s all about understanding the
structural causes that affects the system

3. Stocks
People
Goods
Rabbits
Meters
Gallons
Pollution
RABBITS Whatever
you see
when
picturing
it… those
are stocks!
Let’s take a mental photo of…
let’s say a bunny colony

4. Stocks are like a glass… they fill up… or drain out…

5. FLOWS
People/year
Goods/Shift
Rabbits/Month
Meters/Second
Pollution/year
Unit/Time
How do you fill up/drain out that glass?

6. Fills it
Rabbits
Births Deaths
Drains
it
Warning!
Rabbits in the
area

7. If it’s not a stock… if it’s not a flow
It‘s either an auxiliary variable or a
constant.

8. Population Dynamics
Conceptual
Model
Or…
Stock
and
flows
model

9. Our first model
Can you picture it? What’s the main stock here??
What’s feeding that stock? What are the flows?
Let’s go to a warehouse… a quite simple one

10. Our first model: The bones
It should look something like this:

11. Let’s build that up!!!
Flow

12. Let’s build that up!!!

13. Now some ecuations

15. Performance Indicators

17. Simulation!!!

18. Results

19. Mario Andrés López
mlopez0301@gmail.com