Systems Analysis and Design: Designing Interfaces and Dialogues

Designing Interfaces and Dialogues

• The design of interfaces and dialogues defines the manner of human-computer interaction, providing a uniform structure for finding, viewing, and invoking system components.
• A good human-computer interface should provide a uniform structure for finding, viewing, and invoking system components.

The Process of Designing Interfaces and Dialogues

• The process of designing interfaces and dialogues is a user-focused activity that involves prototyping methodology, including:
  • Collecting information
  • Constructing a prototype
  • Assessing usability
  • Making refinements
• To design usable interfaces and dialogues, one must answer the who, what, where, and how questions.

Deliverables and Outcomes

• The deliverables of designing interfaces and dialogues include:
  • Creation of a design specification
  • The specification includes:
    • Narrative overview
    • Sample design
    • Testing and usability assessment
    • Dialogue sequence
• Dialogue sequence refers to the ways a user can move from one display to another.

Interaction Methods and Devices

• Human-computer interfaces define the method of interaction, which includes:
  • Command language interaction
  • Menu interaction
  • Form interaction
  • Object-based interaction
  • Natural language interaction
• Each interaction method has its own characteristics, such as:
  • Command language interaction: uses explicit statements to invoke operations
  • Menu interaction: provides a list of system options for user selection
  • Form interaction: uses data fields formatted like paper-based forms
  • Object-based interaction: uses symbols to represent commands or functions
  • Natural language interaction: uses conventional spoken language as input

Hardware Options for System Interaction

• Hardware devices used to support interaction include:
  • Keyboard
  • Mouse
  • Touch screen
  • Light pen
  • Joystick
  • Graphics tablet
  • Trackball
  • Voice
• Each device has its strengths and weaknesses, and selection should be guided by the needs of the user.

Designing Interfaces

• Designing interfaces involves:
  • Structuring and controlling data entry fields
  • Providing feedback
  • Designing online help
• Forms should have standard formats, use left-to-right, top-to-bottom navigation, and provide flexibility and consistency.

Designing Layouts

• Designing layouts involves:
  • Using standard formats similar to paper-based forms and reports
  • Providing left-to-right, top-to-bottom navigation
  • Flexibility and consistency
• Several rules should be considered when structuring data entry fields, including:
  • Never requiring data that is already online or can be computed
  • Providing default values when appropriate
  • Making clear the type of data units requested
  • Using character replacement when appropriate
  • Providing formatting examples

Providing Feedback

• Providing feedback involves:
  • Status information: keeping the user informed of what's going on
  • Prompting cues: telling the user when input is needed and how to provide it
  • Error or warning messages: informing the user of errors or warnings

Providing Help

• Providing help involves:
  • Placing yourself in the user's place
  • Designing usable help messages, including:
    • Simplicity
    • Organization
    • Showing the user how to perform an operation

Designing Dialogue

• Designing dialogue involves:
  • Designing the dialogue sequence
  • Building a prototype
  • Assessing usability
• Dialogue design involves:
  • Consistency
  • Error handling
  • Shortcuts and sequence
  • Reversal
  • Feedback
  • Closure
  • Ease
• Dialogue diagramming is a formal method for designing and representing human-computer dialogues.

Designing Interfaces and Dialogues in Graphical Environments

• Graphical interface design involves:
  • Becoming an expert user of the GUI environment
  • Understanding available resources and how they can be used
  • Understanding standards for menus and forms