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

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Presentation on theme: "1 Systems & Systems Analysis Yale Braunstein School of Information Management & Systems UC Berkeley."— Presentation transcript:

1 1 Systems & Systems Analysis Yale Braunstein School of Information Management & Systems UC Berkeley

2 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 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 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 5 Functions of the Systems Analyst 1. Forms design & control 2. Procedure writing & procedure manual control 3. Records management 4. Report control 5. Office & workplace layout 6. Work simplification studies (This is not an exhaustive list.)

6 6 SYSTEM DEVELOPMENT METHODOLOGIES

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

8 8 Waterfall Development Method Evaluation!

9 9 More detail 1. Define problem 2. Outline system study 3. Obtain background information & understand interactions 4. Understand existing “system” 5. Define system requirements 6. Design new system / generate alternatives 7. Design system controls 8. Prepare cost comparisons 9. Sell system to management 10. Provide for implementation, follow-up, evaluation

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

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

12 12 Parallel Development Method

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

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

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

16 16 How Prototyping Works

17 17 Throwaway Prototyping

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

19 19 How broad should the analysis be? What is the system being studied?  Look at one or more of five levels: 1. Entire firm, organization 2. One division 3. Departmental interaction 4. Functional areas within a department 5. A specific problem area within a function

20 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 21 “Black-box” models INPUTS OUTPUTS External Environment

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


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