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Systems & Systems Analysis

Systems & Systems Analysis. Yale Braunstein School of Information Management & Systems UC Berkeley. Working Definition of “System”. A system is a network of inter-related procedures joined together to perform an activity or accomplish an objective

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Systems & Systems Analysis

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  1. Systems & Systems Analysis Yale Braunstein School of Information Management & SystemsUC Berkeley

  2. Working Definition of “System” • A system is a network of inter-related procedures joined together to perform an activity or accomplish an objective • (Note that the level of technology is NOT specified—there are low-tech systems as well as high tech systems) • (Also note that the “breadth” of the system is not specified. More on this later.)

  3. So, what is a “procedure” ? • A procedure is the precise series of instructions that that explain: • What is to be done • Who will do it • When it will be done • How … • (Note the parallels to programming terminology)

  4. Types of Systems • Open system: does not provide for its own control • Closed system: automatically controls or modifies it own operations A recurring thought: It is important to look at how the system handles exceptions.

  5. Functions of the Systems Analyst • Forms design & control • Procedure writing & procedure manual control • Records management • Report control • Office & workplace layout • Work simplification studies (This is not an exhaustive list.)

  6. SYSTEM DEVELOPMENT METHODOLOGIES

  7. What Is a Methodology? • A formalized approach or series of steps • Examples • Process-Centered • Data-Centered • Object-Oriented

  8. Waterfall Development Method Evaluation!

  9. More detail • Define problem • Outline system study • Obtain background information & understand interactions • Understand existing “system” • Define system requirements • Design new system / generate alternatives • Design system controls • Prepare cost comparisons • Sell system to management • Provide for implementation, follow-up, evaluation

  10. Pros and Cons of the Waterfall Method Pros Cons Design must be specified on paper before programming begins Identifies systems requirements long before programming begins Long time between system proposal and delivery of new system [Digression on “internet time” goes here.]

  11. Alternatives to the SDLC* • Parallel Development • Rapid Application Development (RAD) • Phased Development • Prototyping • Spiral Development • Packaged Systems *Systems development life cycle

  12. Parallel Development Method

  13. Pros and Cons of Parallel Development Pros Cons Reduces Scheduled Time Still Uses Paper Documents Less Chance of Rework Sub-projects May Be Difficult to Integrate

  14. CASE tools JAD sessions Fourth generation/visualization programming languages Code generators Rapid Application Development

  15. Phased development A series of versions Prototyping System prototyping Throw-away prototyping Design prototyping Three RAD Categories

  16. How Prototyping Works

  17. Throwaway Prototyping

  18. Criteria for Selecting the Appropriate Methodology • Clear user requirements • Familiar technology • Complexity • Reliability • Time schedule • Schedule visibility

  19. How broad should the analysis be?What is the system being studied? • Look at one or more of five levels: • Entire firm, organization • One division • Departmental interaction • Functional areas within a department • A specific problem area within a function

  20. The “sub-optimization” problem • Sub-optimal: what is best from the narrow point-of-view may not be best when other functions, divisions, etc., are taken into consideration. • Similar to “externalities” in economics • Examples: • Freight & passenger service using same routes • Internal & external networks • Carriers & content providers • “Sub-optimal” is different from “non-optimal”

  21. “Black-box” models OUTPUTS INPUTS External Environment

  22. Sources • Text, Chapter 1 • “History of Project Management”

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