Ambiguity and Specificity

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Ambiguity and Specificity

• Sriram Mohan

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Problem

• Specification must be easy to understand and must
  be clear.
• Balancing the two might be difficult
• Must be easy enough for the client to understand
• Must be unambiguous for the developers

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Light Box Exercise

• After On pushed but before Off pushed system is
  termed power on.
• After Off pushed but before On pushed system is
  termed power off.
• Since most recent On press if count has been
  pressed an Odd/Even number of times, Odd/Even
  shall be lit.
• If either light burns out, the other shall flash
  every 1 second.

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On
Off
Duty Cycle A
On
Off
Duty Cycle B
0
1
2
5
6
3
4
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Techniques for Disambiguation

• How do we detect it?
• Memorization technique
• Emphasis technique
• How do we avoid it?
• Use natural language if possible
• Use pictures and diagrams to illustrate intent
• Communicate When in doubt ask?
• Augment with technical specs

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Technical Methods for Specifying Requirements

• Finite State Machines

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Technical Methods for Specifying Requirements

• Decision Tables and Decision Trees

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Technical Methods for Specifying Requirements

• Entity Relationship Diagrams
• You will get extra credit for Milestone 3 if you
  develop an ER diagram.

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Technical Methods for Specifying Requirements

• Pseudo code
• What is it?
• We will use it for our design phase in 371.
• For each function(s) that results from an use
  case, you must provide the following information
• Name
• Arguments
• Return Type
• Pseudo code
• You must also develop an architecture diagram.

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System Architecture Diagram