Chapter 2: Design Process

Chapter 2: Design Process

1. Define Interaction Design

   • Idea of designing a system & particularly (often exclusively) the user-facing parts of a system that helps a user perform a task.

2. The Software Lifecycle

   • An attempt to identity the activities which occur in software development.
     • Two Main parties
       • The customer requires the use of the product
       • The designer who must provide the product
   • Activities in the Lifecycle
     • Requirement Specification
     • Architectural design
     • Coding and unit Testing
     • Integration and Testing
     • Operation and Maintenance
     • Detailed Design

3. Usability Engineering

   • Measures be made explicit as requirements
   • The ultimate test of usability based on measurement of user experience
   • Usability Specification
     • Usability attribute/principle
     • measuring concept
     • measuring method
     • now level/ worst level/ planned level/ best case
   • ISO usability standard 9241
     • effectiveness
       • can achieve what you want to?
     • efficiency
       • can you do it without wasting effort?
     • satisfication
       • do you enjoy the process?

4. Iterative Design

   • Design methodology based on cyclic process of prototyping, testing, analyzing & refining a product/process.
   • Prototypes
     • throw-away
     • incremental
     • evolutionary
   • management issues
     • time
     • planning
     • non-functional features
     • contracts

5. Design Rationale

   • Information that explain whys a computer system is the way it is
   • Benefits
     • communication throughout life cycle
     • reuse design knowledge across product
     • enforces design discipline
     • capturing contextual infromation
   • types
     • design space analysis
     • psychological DR
     • process oriented DR

6. Design rules

   • Types of design rules
     • principle
     • standard
     • guidelines

7. principle to support usability

   • learnability
     • synthesizability
     • familiarity
     • generalizability
     • consistency
     • predictability
   • flexibility
     • multithreading
     • substitutivity
     • custimizability
     • dialogue initiative
     • task migratability
   • robustness
     • recoverability
     • responsiveness
     • observability
     • task conformance

8. Scheiderman's eight golden rules

   • reduce short term memory load
   • design dialog to yield closure
   • offer informative feedback
   • strive for consistency
   • enable frequent users to use shortcuts
   • offer error prevention & simple error handling
   • permit easy reversal of actions
   • support internal locus of control