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Part III System Analysis and Design; Programming

Part III System Analysis and Design; Programming. Decision Support Systems Pictorial Model Tools: Excel, VBA, IFPS *. Decision Support Systems (1.2). Supports Decisions Must identify decision criteria (e.g., balance in check writing )

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Part III System Analysis and Design; Programming

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  1. Part IIISystem Analysis and Design; Programming • Decision Support Systems • Pictorial Model • Tools: Excel, VBA, IFPS *

  2. Decision Support Systems(1.2) • Supports Decisions • Must identify decision criteria (e.g., balance in check writing) • “Functions” for most frequently used (significant few) tools • Programming tools for “trivial many” customization

  3. Pictorial Model • Modeling (1.2) (Transformation Function, what is it? what are the significances of using this term?)

  4. Pictorial Model • Consists of Pictorial Diagram and equations (pp. 2-3, 5-2) • Uses numbers to identify equations and their sequence • The number of lines out of an attribute indicates its influence to the entire model.

  5. Pictorial Model • Boundary variables have no predecessor • Boundary variables will become “assumptions” in IFPS programs

  6. Tools: Excel • Quick solution; ready-to-use functions (e.g., pmt, stdevp) • Once set up, users can change input parameters (e.g., interest rate, loan amount) to “reuse” this “program” • Not as flexible but less knowledge in programming is needed.

  7. Tools: VBA • For any programming language, must know “input” and “output” first • All programs can be broken down to sequential, iterative (loops), and selection (if-then) • VBA uses spreadsheet as the source of data (input) and display of results (output) -- see handouts

  8. Tools: VBA • More flexible (e.g., length of annuity table does not have to be pre-determined) • Programming idiosyncrasies (e.g., ‘=‘ means assign and not equal) • Most fundamental functions: a=a+1 (counter) and sum=sum+a • for-next loop and if-then-else (see handouts)

  9. Standard Deviation Example • For Logical Design step, research the process by reading books (document) and look for formula (form) • Definitional Formula is easier to understand (why?) • Computational Formula is more efficient (why?)

  10. Tools: IFPS • 4GL (see 1.3 and 1.6) • Extract equations (i.e., business model) from descriptions • Organize the pictorial diagram starting with the goal (e.g., profit) and work backwards • Once the pictorial model is done, the IFPS program is basically done as well.

  11. Tools: IFPS • Compared to Excel, IFPS can do what-if analysis (manipulate input variables) as well • Goal seeking allows user to pre-determine the outcome and view the possible choice of input variables • Simple graphics and report generation for final decision making

  12. Economic Analysiswhy graphics? • Direction and Magnitude (slope of a curve, coefficient for regression line) • Graphics allow a quick view of the long-term trend • Knowledge of the attributes is more important than the knowledge of the tools • Knowledge of the tool enhances the ability to analyze

  13. Tools: IFPS • “Right” is subjective • Easy-to-use modeling tool (compared to Excel and VBA) allows the management to move into Physical Design and Implementation/ Testing stage (End-user development in Laudon chapter 11, p. 349)

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