IENG 423 Design of Decision Support Systems

1. IENG 423 Design of Decision Support Systems Model Based Decision Support Systems Internet as a Decision Support Tool

2. What are these? • What do you call the one on the left? • The right? Pasted from <http://images.google.com/images?gbv=2&hl=en&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&sa=3&q=toy+car&btnG=Search+images> Pasted from <http://www.hobbyplace.com/plastics/carsindex.php>

3. What’s the difference? • Why do most of us these two object in different categories?

4. How about this? • What do we use these things for? • What makes them different from a toy? • What is its utilize? Pasted from <http://www.upscaleinc.com/presentation/Promenade.asp>

5. Models • It represents the object that it is intended to portray… • …in some important functional way • … it has replicated some functional aspect of the object

6. Models • Models can represent objects that are: • Concrete or theoretical • Real or imagined • Past, current, or… • Future – the way things will be.

7. Models • What is the functionality of this model? • What can it tell us? Pasted from <http://www.hobbyplace.com/plastics/carsindex.php>

8. How about this? • What is the functionality of this model? • What might we use it for? Pasted from <http://www.upscaleinc.com/presentation/Promenade.asp>

9. Models – made in a computer • Architectural, • Engineering, • Interior Design models • What can we do with this that we could not do with physical models?

10. Computer Models • Ares Space Ship Pasted from <http://images.google.com/images?hl=en&client=firefox-a&channel=s&rls=org.mozilla%3Aen-US%3Aofficial&hs=eGt&um=1&sa=1&q=3d+computer+models+ares&aq=f&oq=&aqi=&start=0> Pasted from <http://images.google.com/images?hl=en&client=firefox-a&channel=s&rls=org.mozilla%3Aen-US%3Aofficial&hs=eGt&um=1&sa=1&q=3d+computer+models+ares&aq=f&oq=&aqi=&start=0>

11. Computer Models • Understanding biology Pasted from <http://images.google.com/images?hl=en&client=firefox-a&channel=s&rls=org.mozilla%3Aen-US%3Aofficial&hs=eGt&um=1&sa=1&q=3d+computer+models+ares&aq=f&oq=&aqi=&start=0>

12. A computational model • A computational modeling system for simulating neural behavior at the cellular level using Neuroview. The images shown below are products of work done at WVU by G. Spirou, F. Van Scoy, F. Chirla, D. McLaughlin and G. Goltukhuhyan.

13. What is a model? • For our purposes • A representation of a system that replicates or imitates some functionality of the system

14. Why are models useful to us in decision support? • We can observe and try to understand the behavior of the system • We can understand how the system will respond to changes – • In inputs, • Decision alternatives • In context - different scenarios

15. Example… • Population Growth • Maltusian Growth Model P(t) = P0ert

16. Example – model energy usage in your apartment • You have 5 light bulbs • All 5 are 100 watt bulbs • You turn them all on and off at the same time • So, • 5 bulbs * 20 hours/month * 100 watts= 10,000 watt-hours or 10 kwh • 10 kwh * $0.0663 per kwh = $0.6063 ~61¢

17. Example – model energy usage in your apartment • Ok, this works but not very flexible (why?) • …or generalizable (why?) • So, lets create a new model Electricity cost = (Nbulbs *watts* hours-on)/1000*rate

18. Example – model energy usage in your apartment • Still could be better Electricity cost = Σ(Bwattsi*timei)/1000 * rate Σ(100*5,50*20)/1000 * 0.0663 = 10¢

19. But remember… “All Models Are Wrong Some Models Are Useful” • ….generally attributed to the statistician George Box

20. Have a nice day! That’s all I have to say about that