HCI in the Software Life Cycle

HCI in the Software Process

• The goal is to create user-friendly and reliable interactive systems, focusing on the design process and integrating user-centered design within software development frameworks.
• Software engineering manages the technical and managerial aspects of software development through the software life cycle.
• The software life cycle encompasses all activities from concept formation to retirement.
• Human-Computer Interaction (HCI) considerations are integral to every stage of the software life cycle.

The Software Life Cycle

• Software engineering provides a structured approach for applying techniques to develop systems.
• The software life cycle outlines the activities involved in software development.
• Two main parties involved are the customer (who needs the product) and the designer (who creates it).
• The customer is the individual/group who works with the design team, while the user interacts with the final product.

Activities in the Life Cycle

• Requirements specification: The designer and customer define what the system should do, focusing on desired outcomes, without implementation details.
• Architectural design: Breaking down the system into components and their interactions.
• Detailed design: Refining architectural descriptions, preserving intended behavior.
• Coding and unit testing: Implementing components in an executable language, then testing these units.
• Integration and testing: Integrating and testing the integrated system for correctness.
• Maintenance: Fixing post-release errors and updating to meet new requirements.

The Waterfall Model

• The life cycle activities flow sequentially (like a waterfall).
• This model, though visually simple, doesn't fully reflect the actual dynamics between the activities.
• Activities listed above (Requirements specification through Maintenance) represent the stages of the waterfall model.

Verification

• Verification is evaluating if software meets specifications.
• Its purpose is ensuring correctness according to requirements and specifications.
• Verification answers the question: Are we building the system right?

Validation

• Validation assesses whether the software meets user needs and expectations.
• Its purpose is to determine if the right product is being built.
• Validation answers the question: Are we building the right system?

Usability Engineering

• Usability engineering introduces goals and criteria for evaluating how easy a product is to use.
• It considers user experiences, and the system's overall functional architecture along with user cognitive capacities.
• Usability engineers focus on observable interactions, specifying attributes.
• It involves a usability specification within the requirement specification.

ISO usability standard 9241

• Effectiveness: Can users achieve their goals?
• Efficiency: Can users do things without wasting effort?
• Satisfaction: Is the process enjoyable?

Problems with Usability Engineering

• Usability metrics depend on specific user actions in given contexts, which might not be available at the design stage.
• Usability specifications ensure compliance, but not necessarily overall user-friendliness.
• Issues with defining metrics and time constraints with prototyping.

Iterative Design and Prototyping

• Interactive systems require iterative design and prototyping to ensure accuracy in features and modifications after initial evaluations.
• Prototypes vary in functionality and can range from simple animations to fully functional versions. -Prototyping is useful because it provides a realistic simulation of functionalities before system development completes.
• Iterative design allows for modifications and enhancements, leading to a refined end product and solving issues encountered.

Types of Prototyping

• Throw-away: Used during the early design process and the prototypes are discarded after evaluating results for the final product.
• Incremental: The product is built as a series of independent components, each added successively.
• Evolutionary: The prototype is refined through successive iterations and serves as the basis for the next iteration.

Techniques for Prototyping

• Storyboards: Visual representation of user interactions and overall user journey.
• Limited functionality simulations: Basic, non-interactive versions for visualization and testing concepts.
• High-level programming support: More functional support for testing and validating components more like the finished product, using high-level programming languages.

Design Rationale

• Documents the reasoning behind design choices.
• Enables transparency in decision-making and justifications.
• Relates to activities of reflection/documentation, throughout the entire lifecycle.

Importance of Design Rationale

• Provides clarity and understanding about design decisions.
• Facilitates justification and future reference.
• Ensures consistency with project goals.

Examples of Design Rationale

• User interface design: Justifying layout choices based on user feedback.
• System architecture: Explaining architectural pattern choices.

Process-oriented design rationale

• IBIS method: Using Rittel's IBIS framework (Issue-Based Information System).
• Graphical representation (gIBIS): Showing connections between issues, positions, and arguments.
• Variations of IBIS: Enriching the system with elements like design artifacts or issue hierarchies.
• Overall focus: Capturing/organizing design process discussions and decisions.

Design Space Analysis

• QOC notation: Analyzing the design space using Questions, Options, and Criteria.
• Reflection-based: Creating QOC questions after decisions are made.
• Options and Criteria: Evaluating options against a set of criteria.
• Challenges: Defining suitable questions/criteria.
• Alternative methods: Other decision representation frameworks.

Psychological Design Rationale

• Overview: Focuses on aligning products with user tasks and their psychological aspects.
• Task-Artifact Cycle: Systems designed based on current/future user tasks.
• Evolution of tools: How tools evolve for different user needs and tasks.
• Focus on impact: Understanding the psychological consequences of design decisions.
• Identifying tasks, creating scenarios, and using reflection and documentation are essential elements of psychological design rationale.

This quiz explores the integration of Human-Computer Interaction (HCI) within the software life cycle, emphasizing user-centered design. You'll learn about the structured approach to software development and the roles of customers and designers throughout the process. Perfect for those studying software engineering and HCI.