Docstoc

Prototyping

Document Sample
Prototyping Powered By Docstoc
					Human-Computer
Interaction



Prototyping
the User
Interface
                 1
Lecture Overview
   Definition of prototyping
   Purpose of prototyping
   Merits of prototyping
   Types of prototyping
   Desirable features for rapid prototyping tool

            Prototyping is common in
              almost every field of
               engineering design

                                                2
What is a prototype?
   Prototype = ‘working’ model
   Usually a physical model e.g. car,
    aeroplane
   Full-size or to scale
   Fully or partially functional
   In HCI prototype may be a ‘virtual’
    model – a ‘simulation’

                                          3
Purpose of Prototyping
   To identify user interface (and other)
    requirements - almost impossible to
    specify in advance
     “It is not until users interact with something
     concrete that their rich expertise about their
     working environment will surface.”




                                                      4
Prototyping the User Interface
                         Requirements
                           gathering



        HCI          Build
                                       Test
     guidelines    Prototype


                           Enhance
    Knowledge of            Design
     technology


                            Classic
                           lifecycle

                                              5
    Prototyping
   The Prototyping approach provides continuous
    feedback on the current design situation
   In HCI there will never be fully satisfactory design
    guidelines applicable in all circumstances
   Need not be computer based or have full
    functionality
   Greatly aided by good software tools
      Graphical   editors, construction kits, User
       Interface Management Systems (UIMS)

      Prototyping does NOT mean ‘build in haste’
                                                           6
    Merits of Prototyping
   Requirements capture
      Interface and functional requirements

   Reveals problems/prevents gross mistakes
   Allows evaluation and discussion which fosters
    innovative ideas (from designers and users)
   Users enjoy prototyping and feel involved
   Suggests level of user support needed
   Results in better usability
   Economical way of testing designs


                                                     7
Types of Prototyping
 Software --------- Life -------- Cycle
  Exploratory             „Throw-it-away‟
        Experimental
                            prototypes
   R   a   p i d
                                            (Unstructured
  E v o l u t i o n a r y                   development)

    I n c r e m e n t a l                   (Section-at-a-time )

  Horizontal
       Vertical                   Full

 Fragmentary ------------- Complete
 Divergent -------------- Convergent
                                                               8
Types of Prototyping                    (Cont’d)

   Vertical
       Focus on a specific element and simulate in depth
   Horizontal
       Take a broad perspective but with reduced
        functionality at any point
   Full
       Complete functionality, but less performance than
        final system
   High-fidelity/low-fidelity
       (degree of realism)

                                                       9
Groups Involved in Prototyping

  Designers              End Users




              Managers




                                     10
Desirable Features for Rapid
Prototyping Tool
   Graphical construction of presentation
    layer
       Develop and modify screens
       Import text, graphics and other media in
        various formats
   Dialogue interaction
       Menu building
       Link screens
       Support a variety of I/O devices
       Support a range of types of user interface
                                                     11
Desirable Features for Rapid
Prototyping Tool (Cont’d)
   Functional aspects
       Immediate ‘test drive’
       Allow calling of procedures and programs (either
        internal or external)
       High level language (to control sequencing)
       Suspend time editing (stop/resume)
   Good usability
   Good vendor support


                                                    12
    Prototyping on its Own: Possible
    Limitations
   No coherent conceptual model -> users’ feel system
    has unpredictable components
   Uneven appreciation of various user groups
   Lack of task analysis -> lack of breadth of task
    support
   Failure to fully comply with a style guide -> lack of
    internal and external consistency
   Lack of usability evaluation
   Users involved with prototype development may not
    represent cross-section of users
   Not easy to learn or intuitive for newcomers
                                (see Redmond-Pyle and Moore, 1995)
                                                                13
Prototyping on its Own: Possible Limitations
Further notes




                                               14
Lecture Review

   Purpose of prototyping
   Merits of prototyping
   Types of prototyping
   Desirable features for rapid
    prototyping tool
   Limitations of prototyping on its own


                                            15

				
DOCUMENT INFO