• Where/When did you start at?
1.
Mentally imagined the “abstract” form of the solar system
• High level picture of some number of planets “circling” around the sun
– Motionless, Static picture
–
With planets dynamically moving in orbits and different planes
2.
Wondered how to represent this, regardless of the solution.
3.
Wondered what is my “goal” and the main characteristics of the model that I want to satisfy for this assignment.
4.
Wondered when should I start thinking about this problem and when to work on the solution to the problem --- then started working on it when it got close to my mentally set time - - - then it was step 1.

• How many different solutions did you think about?
– Were these different solutions or new ways to look at the problem? or new ways to represent solutions?
– Glad to just have one solution – did not have time to think of alternatives !!!
• How did you decide on the solution?
1.
Thought about all kinds of things before settling on the solution and then just kept on refining.
2.
Thought about a part of the representation of the solution in abstract form and started refining; then went up and abstracted another part and thought of how to represent it; then refined some more; etc.
3.
Thought about the high level abstraction; started to think about a single planet and everything about it; thought about relationships among planets; etc.

• Do you think the difference is just in representation?
• Could there be truly different solutions (that is something that is in one model that’s not in the other models)?
– Does that mean other models are inaccurate and incomplete?
– Does that mean that this model has extra “stuffs” and therefore it is inaccurate?
Isn’t there just one “understanding” of the solar system?

1. Components/Relationship Description :
1.
Names and description of component functionalities and attributes
2.
Relationships among components: composed of; data passed; interface to; “is a” ; etc.
2. Functional/Usage Flow:
1.
User interface: screen to screen navigation
2.
Data flow and responses to usage “triggers” such as movement of pointers and clicking the button

• How much “Problem” analysis took place?
• Did you think about the problem or just assumed you knew?
• Did you have any question when you started working on this assignment --- but there was no one to ask?
• Did you make any assumptions:
– My work is “probably” good enough
• Number of planets needs to be right
• Don’t need to include the moons
• Orbits need to be included
• Probably don’t have to worry about orbital speed
– If I do need to, I would just use earth days for orbital speed
• Don’t need to worry about describing each planet, such as size, surface temperature, distance from sun, etc.
• Don’t need to “define” the solar system - - - that’s the problem statement !

– What is the physical Solar System ?
• Main components
– Subcomponents
• Attributes of components and subcomponents
• Relationships and possible Interactions among components and sub-components
– What is the Software Systems that models the physical system?
• Main components
– Functionalities
– Attributes (data the functionalities work on)
– Relationships and interactions among these main components
• How far do we refine (depth of model/design)?
• How should we represent the model/design ?

• Some generalization:
– In order to model, provide requirements, even understand the requirements, one needs to understand the system that one is modeling or writing about ( Domain Specific knowledge )---e.g. Solar System
– In order to design the software to model the system one needs to understand the “modeled system” as much as possible: (for Requirements and Design)
• The physical system
• The business system
• The biological system
• The social system
– Design also requires one to understand what are the capabilities and possibilities of the tools that one has (visual, audio, data base, network, languages, etc.)