Unified User Interface Development
C. Stephanidis and A. Savidis

1. Introduction
   • Information Society or Digital Age: interactive software applications and services for:
     • Anyone - variety in users
     • Anywhere - variety in contexts
     • Anytime - variety in situation
     • Anything - variety in purpose
   • Universal Access in the Information Society: the right of all citizens to obtain and maintain access to a society-wide pool of information resources and interpersonal communication facilities, given the varieties of contexts of use.
   • HCI for Universal Access
     • Accessibility
     • High-quality
     • Accessibility vs Interaction Quality
   • Copying with Diversity
     • Users
     • Environment
   • Technical approaches
     • Reactive: Applying add-ons over existing technology, to overcome inherent (to technology) accessibility and quality problems
     • Proactive: Influencing the design and implementation of technology, to avoid inherent accessibility and quality problems
     • Reactive vs Proactive methods
   • Automatic Interface Adaptation
     • Examples
     • User awareness
     • Usage-context awareness
     • Origins of Knowledge Items
       • Knowledge available or inferable prior to initiation of an interaction session (off-line).
       • Knowledge inferable only by analysing interaction monitoring information (on-line).
     • Two Types of Interface Adaptation
       • Adaptability
       • Adaptivity
     • Adaptivity and Adaptability - Complementary Roles
   • Unified interface concept
     • End-User view: An interface tailored to personal attributes and to the particular context of use
     • Design view: An interface design populated with polymorphic artifacts, i.e., artifacts encompassing alternative designs, each alternative addressing specific user- and usage-context- parameter values
     • Engineering view: A repository of implemented dialogue artifacts, from which to select the most appropriate at run-time. Decision making is needed, to decide which artifacts to chose, given end-user- and usage-context- attribute values
     • Unified User Interface - Definition
       • User- and usage-context self-adapting interface, encompassing
       • Alternative implemented dialogue artifacts
       • User- and context- information
       • Decision making capability selecting user- and context- appropriate dialogue artifacts
       • Interface control to apply decisions made
     • Need for a development process
       • Design process
       • Implementation architecture
       • Engineering process
2. Unified Interface Design
   • The need
     • For any given task, diverse user- / context- attribute values may dictate the design of alternative dialogue patterns
     • Hence, given design context (I.e. task), the varying parameters of the design problem (user, context), map to more than one artefacts
     • However, existing practices impose a single artifact per context, within the final design outcome
   • Polymorphic Task Hierarchies
     • Properties
       • Hierarchical task analysis
       • Polymorphism on: (a) task decomposition, (b) physical design specialisation
     • Examples
     • Decomposition Flexibility (styles can be further analysed through any other appropriate design method)
   • Polymorphic Task Decomposition Process
     • Abstract vs Physical tasks
     • Unimorphic vs Polymorphic tasks
     • Sub-tasks vs sub-hierarchies
   • Designing Alternative Artefacts:
     • Construct the space of user / context attributes;
     • Identify when polymorphic decomposition is needed, then produce and enumerate alternative styles;
     • Record design rationale for each alternative style.
   • Space of User Attributes
     • Examples: General computer expertise; Application domain knowledge; Work-role in an organisational context; Motor / sensory / mental abilities; Particular interaction preferences
   • Space of Context Attributes
     • Examples:Environment, Machine
   • User- and Context- Attributes
   • When to Apply Polymorphic Decomposition
   • Recording Design Rationale for Alternative Styles
     • Relationships Among Alternative Styles:
       • Exclusion
       • Compatibility
       • Substitution
       • Augmentation
3. Unified Interface Engineering
   Unified Interface Architecture
   • Context Information Server
     • Role and Behaviour
     • Content
     • Communication
     • Implementation
   • User Information Server
     • Role and Behaviour
     • Content
     • Communication
     • Implementation
   • Decision Making Component
     • Role and Behaviour
     • Content
     • Communication
     • Implementation
   • Dialogue Patterns Component
     • Role and Behaviour
     • Content
     • Communication
     • Implementation
4. Conclusions