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CSE460 Lecture 02

CSE460 Lecture 02

Software Analysis and Design
Complexity
(202101)

B546a9b97d993392e4b22b74b99b91fe?s=128

Javier Gonzalez
PRO

July 02, 2020
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  1. jgs CSE 460 Software Analysis and Design Lecture 02: Complexity

    Dr. Javier Gonzalez-Sanchez javiergs@asu.edu javiergs.engineering.asu.edu | javiergs.com PERALTA 230U Office Hours: By appointment
  2. jgs Previously

  3. jgs 00000001 Previously To create a specification A graphical description

    (blueprint) Understand and capture elements and their relationships in a problem
  4. jgs Complexity

  5. jgs 00000001 The Problem with Complexity 1. The more complex

    the system, the more open it is to total breakdown 2. software crisis: late, over budget, and deficient satisfying requirements
  6. jgs 00000001 Scenarios VS

  7. jgs 00000001 Ignore Complexity When § Forgettable applications § Specified,

    constructed, maintained, and used by 1 person, (isolated developer). § Prototyping: limited purpose and a short life span. § We can afford to throw them away and replace them with a new software rather than attempt to reuse them, modify them, or extend their functionality. Therefore, design them is not relevant.
  8. jgs 00000001 Challenges § Communication gap between the users and

    developers § Trade-Offs: Competing, perhaps even contradictory, requirements in the problem domain. § Quality: usability, reliability, performance, cost, … § Combinatorial explosion of outputs (limited testing) § Management: keep the illusion of simplicity § Labor-intensive vs Product lines
  9. jgs 00000001 Problem § maximum number of chunks of information

    that an individual can simultaneously comprehend is on the order of seven, plus or minus two
  10. jgs 00000001 § Models give us the opportunity to fail

    Blueprint (Model)
  11. jgs 00000001 Alternative Solution * pioneering work on object-oriented programming

    and windowing graphical user interface design "Most software today is very much like an Egyptian pyramid with millions of bricks piled on top of each other, with no structural integrity, but just done by brute force and thousands of slaves". – Alan Kay ACM Queue. Vol. 2, No. 9 - Dec/Jan 2004-2005
  12. jgs 00000001 Alternative Solution New Yorker, June 1992

  13. jgs What to Do?

  14. jgs 00000001 Solution | Understanding the Problem § Independent –

    loosely coupled with one another § Negotiable – Stories are what and why , not how ( 99% ). § Valuable – for the customer! § Estimable – Effort/Cost of design, build, and test. § Small (sized appropriately) § Testable – pass or fail
  15. jgs 00000001 Solution | Modeling the Problem § Primitives Components

    § Separation of Concerns § Common Patterns (relationships) § Hierarchic Structure § Incremental Development: one problem at a time
  16. jgs 00000001 Solution | Modeling the Problem § Primitives Components

    § Separation of Concerns § Common Patterns (relationships) § Hierarchic Structure § Incremental Development: one problem at a time Decomposition Abstraction Encapsulation Inheritance
  17. jgs Case Study Part One

  18. jgs 00000001 Pacman Needs Necessities Wishes Desires Ideas Requirements

  19. jgs 00000001 Pacman I want a Pacman videogame Requirements

  20. jgs 00000001 Pacman Independent loosely coupled with one another Negotiable

    Stories are what and why , not how Valuable for the customer! Estimable Effort/Cost of design, build, and test. Small (sized appropriately) Testable (pass or fail)
  21. jgs 00000001 Homework § Working alone or in a team

    of 2, 3, or 4 define the requirements for the pac- man videogame § Submit a list with at least 25 functional requirements § You can add non-functional requirements (they are extra to the 25 required) § Remember, check each of your candidates for the INVEST properties.
  22. jgs 00000001 Reference Textbook Chapter 1

  23. jgs CSE 460 Software Analysis and Design Javier Gonzalez-Sanchez javiergs@asu.edu

    Fall 2020 Disclaimer. These slides can only be used as study material for the class CSE460 at ASU. They cannot be distributed or used for another purpose.