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human-computer interaction hci design principles usability

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These notes cover the fundamentals of human-computer interaction (HCI), including its definition, importance, and design principles. The document explores different aspects, such as usability considerations, common guidelines for interface design, and the evolution of HCI.

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CHAPTER 1 : INTRODUCTION OF HCI What is HCI? Definition: ○ HCI is a discipline focused on designing, evaluating, and implementing interactive systems for human use and understanding the phenomena surrounding them. ○ Aims to create software an...

CHAPTER 1 : INTRODUCTION OF HCI What is HCI? Definition: ○ HCI is a discipline focused on designing, evaluating, and implementing interactive systems for human use and understanding the phenomena surrounding them. ○ Aims to create software and technology that: People want to use. Are easy to use. Are effective when used. Usable Systems: ○ Easy to learn and remember. ○ Effective, efficient, safe, and enjoyable. Why HCI is Important? Impact of Poor Design: ○ Frustrates users and reduces usability. Affects: ○ Effectiveness: Helps achieve goals accurately. ○ Productivity: Saves time and effort. ○ Morale: Positively influences users' motivation. ○ Safety: Enhances security and reduces risks. Examples: ○ Children learn better through engaging computer-aided systems. ○ People with disabilities improve productivity and morale. ○ Air traffic systems ensure pilots' safety. The Goal of HCI Usability Design: ○ Create systems that meet specific user goals with: Effectiveness Efficiency Satisfaction ○ Focuses on usability within a defined context. The Interdisciplinary Field of HCI Combines knowledge from various fields: ○ Machine Side: Computer Science: Technology and applications. ○ Human Side: Cognitive Science: Human capabilities. Psychology: How humans interact with systems. Sociology: Group interactions and collaboration. Anthropology: Interaction with environments. Human Factors Engineering: Usable design principles. Universal Usability Designing products usable by all, considering human diversity. Key Considerations: 1. Personality Differences: Anxiety, gender differences, preferences. 2. Cognitive and Perceptual Abilities: Interpretation and sensory processing. 3. Cultural and International Diversity: Formats, etiquette, language, and metaphors. 4. Users with Disabilities: Technology for vision, hearing, learning, and mobility challenges. 5. Older Adults: Features for accessibility (e.g., adjustable fonts, colors). 6. Younger Users: Attention span, dexterity, creativity, and socio-economic diversity. The Evolution of HCI Shift from text-based systems to graphical and interactive systems. Evolving technologies aim for better user experience and efficiency. The Impact of HCI 1. On Society: ○ Reduced training required for most devices. ○ Examples: Touch screens and voice controls. 2. On Culture: ○ Changes in how we use free time (e.g., smartphones, games). ○ Influences social interactions and relationships. The Future of HCI Emerging technologies: ○ Holograms ○ Wearable Technology: Augmented and virtual reality. ○ Robotics ○ Speech Recognition: Voice-based interactions. CHAPTER 2 : Introduction to Guidelines, Principles, and Theories Key Issues: Poorly designed interfaces with cluttered displays, inconsistent layouts, and unnecessary text can lead to poor user performance, minor slips, serious errors, and frustrated users. Solutions: Use guidelines, principles, and theories to improve interface design and usability: ○ Theory: General ideas explaining phenomena (e.g., Cognitive Theory: Short-term and long-term memory in problem-solving). ○ Principle: General, broadly applicable rules (e.g., Planning task sequences). ○ Guideline: Specific advice for systems or devices (e.g., Steps for simplifying interface navigation). 2. Guidelines Derived from practical experience and empirical studies to: ○ Establish shared understanding among designers. ○ Promote design consistency. Common Guidelines 1. Navigating the Interface ○ Ensure efficient navigation by: Standardizing task sequences. Using descriptive and unique headings. Providing checkboxes for binary/multiple choices. Using thumbnails for image previews. 2. Organizing the Display Based on Smith and Mosier (1986): ○ Maintain data display consistency (e.g., consistent terminology, color schemes). ○ Facilitate efficient information assimilation. ○ Minimize memory load (e.g., proper labels). ○ Ensure compatibility between data display and entry. ○ Provide flexibility for user-controlled displays. 3. Getting the User’s Attention Use: ○ Visual cues: Underlines, arrows, large fonts, unique font styles, blinking animations. ○ Color: Highlight using contrasting colors. ○ Audio: Soft tones for positive feedback; harsh tones for emergencies. 4. Facilitating Data Entry Smith and Mosier’s (1986) objectives: ○ Consistent input methods. ○ Minimal user input (e.g., buttons instead of typed commands). ○ Minimized memory load (e.g., forms over command lines). ○ Data entry compatibility with the display. ○ Flexible entry options (e.g., user-controlled input formats) 3. Principles More fundamental and project-independent than guidelines. Govern key design decisions. Core Principles 1. Determine User’s Skill Level: ○ Design based on user categories: Novices: Require simple instructions, limited vocabulary, and constructive feedback. Intermittent Users: Use consistent actions, meaningful messages, and context-dependent help. Experts: Require shortcuts, rapid response times, and minimal distractions. ○ Accommodate diverse user groups using a multi-layer approach: Begin with basic features; introduce advanced functionalities progressively. 2. Identify the Tasks: ○ Conduct task analysis by: Observing and interviewing users. Breaking down high-level tasks into smaller steps. Prioritizing tasks based on frequency. 3. Choose an Interaction Style: ○ Interaction styles and their pros/cons: Direct Manipulation: Intuitive but challenging to program (e.g., AR/VR interfaces). Menu Selection: Easy to use but requires careful task analysis. Form Fill-In: Rapid for experienced users but requires label clarity and error handling. Command Language: Efficient for experts but prone to errors and requires training. Natural Language: Easy to learn but often unpredictable and complex. 4. Apply the 8 Golden Rules of Interface Design (by Shneiderman): ○ Strive for consistency. ○ Cater to universal usability. ○ Offer informative feedback. ○ Design dialogues to yield closure. ○ Prevent errors. ○ Permit easy action reversal. ○ Support internal locus of control. ○ Reduce short-term memory load. 5. Prevent Errors: ○ Provide clear instructions and constructive error messages. ○ Design safeguards (e.g., gray out unavailable options, restrict input types). 4. Theories Theories provide structured explanations and tools for decision-making. Types of Theories 1. Descriptive: ○ Define user interfaces using consistent terminology and taxonomies. 2. Explanatory: ○ Illustrate event sequences with causal relationships. 3. Prescriptive: ○ Offer guidelines for design decisions. 4. Predictive: ○ Compare design alternatives using metrics like speed and error rates. Theories by Human Interaction Type 1. Motor: Skills like pointing, clicking, or dragging. 2. Perceptual: Visual, auditory, and tactile sensory input. 3. Cognitive: Problem-solving through memory functions. CHAPTER 3 : Design 1. Design Process Nature of Design: Design is inherently creative, unpredictable, and cannot be statistically quantified. It requires balancing: 1. Technical feasibility. 2. Aesthetic appeal to attract and satisfy users. Key Characteristics (Rosson and Carroll, 2002): 1. Design is a process – iterative and non-hierarchical. 2. Radical transformation – involves discovering new goals. 3. Dynamic – constantly evolving as solutions are refined. 2. Design Process Phases 1. Phase 1: Requirements Analysis ○ Collects all system/device requirements, documented as a Requirements Specification. ○ Three Main Components: Functional Requirements: Define system behavior (e.g., an ATM validating PINs). Non-functional Requirements: Specify system operation criteria (e.g., performance, reliability). User Experience Requirements: Define interaction/navigation features (e.g., navigation menus, clear instructions). 2. Examples: ○ E-commerce Website: Functional: Allow item purchases and suggest related merchandise. Non-functional: Access accounts anytime to modify details. UX: Keep navigation menus visible at all times. ○ ATM: Functional: Validate PIN codes. Non-functional: Provide a 15-second selection timeout. UX: Commands should respond within 0.5 seconds. ○ Mobile Messaging App: Functional: Save unsent messages for later when out of service. Non-functional: Send messages within 2 seconds. UX: Allow UI customization (color schemes, sounds, etc.). 3. Phase 2: Preliminary and Detailed Design ○ Preliminary Design: Focuses on high-level architecture (conceptual/architectural design). Examples: Sketches, low- and high-fidelity prototypes. ○ Detailed Design: Plans the specifics of interactions, using design tools, patterns, and best practices. 4. Phase 3: Build and Implementation ○ Converts the designs into actual software and hardware (e.g., coding in Java, C++). ○ Output: Fully functional system. 5. Phase 4: Evaluation ○ Validates the implementation to ensure compliance with requirements and design goals. ○ Includes various evaluation methods (covered in a separate topic). CHAPTER 4 : Evaluation and the User Experience 1. Introduction Designers often get overly attached to their creations, leading to inadequate evaluation. Key Determinants of an Evaluation Plan: 1. Stage of design (early, middle, late). 2. Novelty of the project (well-defined vs. exploratory). 3. Costs of product and allocated finances for testing. 4. Number of expected users. 5. Criticality of the interface (e.g., life-critical systems vs. casual applications). 6. Time availability. 7. Experience of the design and evaluation team. 2. Expert Reviews Involves obtaining feedback from individuals with expertise in application or UI domains. Outcome: A report identifying problems or providing recommendations for improvement. Expert Review Methods 1. Heuristic Evaluation: ○ Experts assess the interface using a list of design heuristics (e.g., Jakob Nielsen’s 10 Usability Heuristics). ○ Suitable for quick decision-making. 2. Guidelines Review: ○ Checks interface compliance with organizational or other guideline documents. ○ May require significant time due to lengthy guideline lists. 3. Consistency Inspection: ○ Verifies consistency in terminology, fonts, colors, layouts, and input/output formats across the interface and supporting documents. 4. Cognitive Walkthrough: ○ Experts simulate user interactions to perform typical tasks, focusing on high-frequency and critical tasks like error recovery. ○ Useful for exploratory browsing interfaces and those requiring training. 5. Formal Usability Inspection: ○ Conducted like a courtroom meeting where experts discuss interface strengths and weaknesses. ○ Provides educational value for novice designers but requires extensive preparation. 3. Usability Testing Definition: Evaluates how easy a system is to use, assessing its usability as a quality attribute. Usability Testing Methods 1. Paper Mockups and Prototyping: ○ Early testing with low-fidelity prototypes to assess user reactions to wording, layout, and sequencing. ○ Tools: Pen and paper, Balsamiq, Mockingbird, Wireframe, Adobe XD. 2. Other Testing Variants: ○ A/B testing. ○ Discount usability testing (low-cost testing methods). ○ Competitive usability testing. ○ Universal usability testing (evaluating accessibility for all user groups). ○ Field testing with portable labs. ○ Remote usability testing. ○ "Can-you-break-this" tests. ○ Think-aloud protocols. Steps in Usability Testing 1. Define clear goals. 2. Create scenarios and tasks for participants. 3. Recruit representative users. 4. Conduct testing and record observations. 5. Analyze results and make recommendations. 4. Survey Instruments Purpose: Gather written feedback from users as a supplement to usability tests and expert reviews. Keys to Success: ○ Clear goals. ○ Focused survey items that align with goals. Survey Goals 1. Gather subjective impressions of interface aspects: ○ Representations of task domain objects and actions. 2. Understand user demographics: ○ Age, gender, education, experience with computers, job roles, personality styles. 3. Identify reasons for non-usage: ○ Complexity, slow performance, inadequate features. 4. Measure user familiarity with features: ○ Printing, shortcuts, tutorials. 5. Assess emotional responses: ○ Feelings of control, clarity, frustration, or excitement. Comparison: Usability Testing vs. Expert Review Usability Testing: Focuses on real users interacting with the system. Expert Review: Relies on professional expertise to identify design flaws. CHAPTER 5 : Direct Manipulation and Immersive Environments Introduction Term Origin: Introduced by Ben Shneiderman in 1983. Context: Shift from command-line interfaces (user remembers and types system labels and object names) to more visual and interactive systems. Historical Example: XEROX Star (1982). What is Direct Manipulation (DM)? Definition: An interaction style where users act on objects directly on the screen through physical, incremental, and reversible actions. Characteristics: ○ Immediate visibility of effects on the screen. ○ Based on Graphical User Interfaces (GUIs) and WYSIWYG (What You See Is What You Get). ○ Combines menu-based interaction with actions like dragging and dropping. Goal: Minimize user learning curve. Advantages of Direct Manipulation 1. Visual Task Representation: Concepts are visually presented. 2. Ease of Learning: Minimal effort to understand the interface. 3. Retention: Users remember how to use the system easily. 4. Error Avoidance: Intuitive design reduces mistakes. 5. Exploration Encouraged: Safe to try out features without adverse effects. 6. High Subjective Satisfaction: Users feel in control and enjoy the interaction. Disadvantages of Direct Manipulation 1. Overloaded Visuals: ○ Representations may be too spread out or cluttered. 2. Confusion in Complex Designs: ○ High-level diagrams (e.g., flowcharts) can overwhelm users. 3. Screen Space Limitations: ○ Forces valuable information off the screen. 4. Learning Curve for Visuals: ○ Users must familiarize themselves with graphical elements. 5. Potential Misleading Representations: ○ Visuals may not always be intuitive. 6. Keyboard Efficiency: ○ Typing commands can sometimes be faster. Translational Distances in Direct Manipulation Refers to the indirectness between a user's physical actions and the corresponding virtual responses. Types: 1. Weak Translational Distance: Large distance between user action and system response. Examples: Mouse, trackpad, joystick. 2. Medium Translational Distance: Reduced distance; actions are more direct. Examples: Touchscreens (mobile phones, kiosks, desktops). 3. Strong Translational Distance: Actions involve gestures or physical interaction with virtual objects. Examples: Data gloves, gesture-based interfaces. 4. Immersive: Combines DM with Virtual Reality. High engagement where users feel entirely involved. The environment dynamically adjusts to user movements. Examples of Immersive Environments Immersive experiences are designed to: ○ Enhance user engagement. ○ Simulate real-world scenarios. Common application areas include virtual reality platforms where the scenery changes as the user moves.

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