systems & systems analysis
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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 - PowerPoint PPT PresentationTRANSCRIPT
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Systems & Systems Analysis
Yale Braunstein
School of Information Management & SystemsUC Berkeley
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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.)
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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)
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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.
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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.)
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SYSTEM DEVELOPMENT METHODOLOGIES
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What Is a Methodology?
A formalized approach or series of steps
Examples Process-Centered Data-Centered Object-Oriented
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Waterfall Development Method
Evaluation!
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More detail1. 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
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Pros and Cons of the Waterfall Method
Pros Cons
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.]
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Alternatives to the SDLC*
Parallel Development
Rapid Application Development (RAD)
Phased Development
Prototyping
Spiral Development
Packaged Systems
*Systems development life cycle
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Parallel Development Method
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Pros and Cons of Parallel Development
Pros Cons
Reduces Scheduled Time
Less Chance ofRework
Still Uses PaperDocuments
Sub-projects May BeDifficult to Integrate
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Rapid Application Development
CASE tools
JAD sessions
Fourth generation/visualization programming languages
Code generators
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Three RAD Categories
Phased development A series of versions
Prototyping System prototyping
Throw-away prototyping Design prototyping
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How Prototyping Works
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Throwaway Prototyping
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Criteria for Selecting the Appropriate Methodology
Clear user requirements
Familiar technology
Complexity
Reliability
Time schedule
Schedule visibility
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How broad should the analysis be?
What is the system being studied?
Look at one or more of five levels:1. Entire firm, organization2. One division3. Departmental interaction4. Functional areas within a
department5. A specific problem area within a
function
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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”
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“Black-box” models
INPUTS OUTPUTS
External Environment
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Sources
Text, Chapter 1
“History of Project Management”