CS252. User Interface Design

Lecture Outline for Feb. 4
Overview of User-Centered Design


  1.     Types of Menus 
    Pull-down menu:


    Pop-up menu:


    Tear-off menu:


    Cascading menu:


    Scrolling menu:



    Option menu:



    Toolbars and value controls can also be considered as menus

    Macintosh and OSF/Motif support all forms; MS Windows only supports pull-dow
n, pop-up, and cascading






    Advantages of greater depth and less breadth:
2.     Motivation
     Key attributes of software (according to many software engineering texts)
          reliability
          maintainability
          modifiability
          efficiency
          usability
     Usability is last on the list, but implicit to them all



     Usability criteria in terms of mental models and conceptual models:


          Effectiveness:

          Efficiency:

          Satisfaction:


     "Efficiency" has three components:
          Ease of learning: 





          Ease of use:






          Throughput:







     Usability doesn't just happen   it's planned from the outset







3.   User-Centered Design -- A Case Study
     User-Centered Design (UCD) changes the way software is designed



     Principles were originally discussed in [Gould & Lewis 1985]
     Case study of British Air Traffic Control System [cited in Preece 1994]
     Original system:




     Design goal:


     Issues in design methods:



     Other issues:



     Design steps employed:
          (1) Evaluation of the controller's task


          (2) Development of first-cut design


          (3) Establishment of user systems design group


          (4) Concept testing and user feedback


          (5) Production of upgraded prototype


          (6) Road-show to the five airports


          (7) Development of system specification


          (8) Build and install system


          (9) Establish new needs


     What was the impact of adding user involvement to software development?
          Suggestions from Heathrow controllers (first feedback stage):
               Modified information requirements
               Different screen layouts for different controllers and tasks
               Greater use of color to indicate exceptional situations (and to adapt to
                    different ambient lighting)
               Editing facilities to allow rapid update


          Suggestions from other users ("road-show" of prototype):
               Ability to make up own pages for specific local conditions


          Further user suggestions (second feedback stage)
               Local installation must be modifiable by any knowledgeable user
               User-controlled resizing, repositioning, recoloring
               Software tools for specifying control configurations