HF Exam1 Review
Page 5: Most Important Slides
These slides account for approximately 95% of the exam content
Page 6: Chapter Overview
Chapter 1: Focus on ergonomics and design principles
Page 7: Key Ergonomic Concepts
Types of Ergonomics:
Cognitive Ergonomics
Physical Ergonomics
Mechanical/Psychophysiological Perspectives
Cognitive/Behavioral Perspectives
Human-Machine Systems
Neuro-Ergonomics
Page 8: Costs of Ignoring Ergonomics
Reduced production output
Increased lost time
Higher medical costs
Increased absenteeism
Lower quality of work
Higher incidences of injuries and strains
Increased likelihood of accidents and errors
Increased labor turnover
Reduced spare capacity to handle emergencies
Intangible Losses: To be further identified
Page 9: Basic Ergonomic Model
Human-Machine System (HMS): Involves one or more humans interacting with machines/tools in an environment to complete tasks
Human-Computer Interaction (HCI): Focus on interfaces between humans and computers
Human-in-the-loop Model: Emphasizes the human role in task completion
Page 10: Demand/Capacity Gaps
Gaps: Occur when task demands exceed worker/user capacities, affecting performance over time
Page 11: Compensatory Behavior
Definition: Ways individuals mitigate demands to accomplish tasks
Examples:
Creating subtasks
Slowing down work pace
Altering posture for leverage
Using both hands instead of one
Page 12: Identifying Gaps
Evaluation Steps:
Describe work objectives and performance standards
Describe worker/user characteristics
Describe spatial and temporal relationships between workers and their environment
Page 13: Types of Human-Machine Systems
Power Supply Types:
Manual System: Human to Human
Mechanical System: Human to Machine
Automated System: Machine to Machine
Page 14: Basic Functions of Human-Machine Systems
Sensing: Information Reception
Information Storage
Information Processing and Decision Making
Action Functions
Page 15: Characteristics of Human-Machine Systems
Purposive: Systems have defined goals.
Hierarchical: Systems can have hierarchical structure.
Environment Dependent: System functions relate to environmental conditions.
Functionality: Components serve specific functions towards goals.
Interactivity: Components interact with each other.
Inputs/Outputs: Systems include defined inputs and outputs.
Page 16: Chapter 2 Overview
Focus on anthropometry and its relevance in ergonomics
Page 17: Anthropometry Needs
Cases:
Case 1: Workplace design
Case 2: Consumer products
Case 3: Biomechanical modeling
Case 4: Clinical and rehabilitation issues
Study Objective: Measure human body structures
Page 18: Types of Anthropometry Data
Structural Data: Taken in standard positions (static)
Functional Data: Measured in various work postures (dynamic)
Newtonian Data: Analyzed in biomechanical evaluations concerning strength
Page 19: Understanding Percentiles
Definition: Percentiles show the value below which a given percentage falls.
5th Percentile: 162 cm (only 5% smaller)
50th Percentile: 173 cm (50% smaller)
95th Percentile: 185 cm (95% smaller)
Page 20: Normal Distribution Analysis
Key Parameters:
Mean (m): Central tendency measure
Standard Deviation (SD): Measure of dispersion
Formulas:
Mean: m = Σxi / n
Std Dev: SD = √(Σ(xi - m)² / (n - 1))
Page 21: Percentile Example
Calculating Percentiles using Given Data:
Example: 25th percentile, 75th percentile from provided popliteal height data.
Z-scores: Used for percentile calculations based on population statistics.
Page 22: Inclusive Design Principles
Approaches:
Design for the Mean
Design for Extremes (short/small and tall/large users)
Design for Adjustability
Additional Notes: Include principles for various design types.
Page 23: Design for Adjustability
Definition: Accommodating a range of users physiologically (5th percentile female to 95th percentile male)
Application Frequency: Common in consumer products; rare in workplaces
Page 24: General Approach to Anthropometric Design
Define user population
Relevant body dimensions
Select design principles
Access anthropometric tables
Determine population accommodation percentage
Account for clothing allowances (optional)
Calculate specific dimensions
Page 25: Design Factors in Anthropometry
Correlation Between Dimensions:
Formulas for Combining Dimensions:
Mean and standard deviation relationships for added/composed dimensions
Page 26: Directional Terms Overview
Key Terms:
Superior, Inferior, Lateral, Medial, Posterior, Anterior, Sagittal, Coronal, Transverse
Page 27: Directional Terms Continuation
Definitions of Orientation:
Example: Anterior = ventral, Posterior = dorsal
Movements related to positioning
Page 28: Muscle Movement Types
Definitions:
Abduction: Away from midline
Adduction: Towards midline
Circumduction: Circular movement
Flexion/Extension: Bending/Straightening of joints
Page 29: Joint Range of Motion (ROM)
Importance of Measuring ROM:
Define physical impairments and set norms for different postures
Factors limiting ROM
Page 30: Strength and Anthropometry
Why analyze strength?
Identify risks for tasks demanding strength
Inter-individual strength variability
Page 31: Properties of Strength
Key Concepts in Strength Measurement:
Maximum Voluntary Contraction (MVC), Safety Factor, Types of Forces
Page 32: Strength Equation Overview
Understanding Strength Equation:
Moment of inertia and its calculation in relation to muscle contractions
Page 33: Estimating Segment Lengths
Usage of anatomical landmarks for segment length
Body segment lengths as a fraction of body height.
Page 34: Segment Mass Characteristics
Table of Segmental Body Parameters:
Center of mass, segment length in relation to proximal/distal regions
Page 35: Mass Moment of Inertia
Definitions:
Mass and inertia as measures of resistance to changes in an object’s motion
Newton’s Laws of Motion and Equilibrium
Page 36: Parallel Axis Theorem
Understanding Body Segment Rotations:
Radius of Gyration and its definitions regarding segment rotation
Page 37: Moment of Inertia Calculations
Inertia Respective to Segment Lengths and Centers of Mass:
Calculating inertia using provided formulas and data
Page 38: Chapter 3 Overview
Focus on design and prototyping principles
Page 39: Understanding Design Process
Key Components of Design:
Front-end analysis, knowledge of human capabilities, iterative design, evaluation
Page 40: Human Factors Design Cycle Goals
Primary Aims:
Safety, Productivity/Performance, Satisfaction/Comfort
Page 41: Interaction Design Activities
Core Activities:
Designing alternatives, establishing requirements, prototyping, evaluating
Page 42: Importance of Task Analysis
Definition and Benefits:
Systematic examination of processes to improve efficiency and safety
Page 43: Benefits of Task Analysis
Outcomes of Effective Task Analysis:
Facilitates tool design, enhances understanding, training, education, standardization
Page 44: Types of Task Analysis
Common Methods:
Hierarchical Task Analysis (HTA), Cognitive Task Analysis (CTA), GOMS Analysis
Page 45: Plans in HTA
Significance of Plans:
Describe conditions and sequences in task completion, accommodate task complexity
Page 46: Types of Plans in HTA
Categories for Task Plans:
Fixed/contingent sequences, choices, optional completion, concurrent operations
Page 47: Hierarchical Task Analysis Example
Illustrating HTA with Specific Tasks:
Breakdown of actions involved in making a cup of tea using sequential plans
Page 48: Limitations of HTA
Weaknesses in HTA:
Difficulty in representing task coordination and dynamic behaviors
Page 49: Cognitive Task Analysis (CTA)
Focus Area:
Understanding cognitive processes users apply in task completion
Page 50: GOMS Method Overview
Components of GOMS:
Goals, Operators, Methods, Selection rules for evaluating tasks
Page 51: Performing Task Analysis Steps
Define purpose and collect needed data
Organize and interpret task data
Identify user personas, scenarios
Page 52: Defining Purpose in Task Analysis
Steps to Clarify:
Identify tasks to analyze and the necessary information to collect
Page 53: Collecting Task Data
Methods of Data Collection:
Observations, interviews, surveys, automatic data collection
Page 54: Interpreting Data
Analysis Techniques:
Use goal/task hierarchies, flow, duration, and communication to formulate conclusions
Page 55: Innovating from Collected Data
Utilizing Data for Design Improvements:
Use cases, user scenarios, workload analyses
Page 56: User Personas
Purpose of Developing Personas:
Synthesize user characteristics to guide design, avoid idealization
Page 57: Task Descriptions in Scenarios
Understanding Daily vs Necessary Tasks:
Scenarios describe realistic user interactions and overlaps with use cases
Page 58: Hierarchical Task Structure
Principles of HTA:
Describe tasks hierarchically to effectively achieve user goals
Page 59: Evaluation Methods Overview
Various Stages of the Design Process:
Early and iterative evaluations improve design to meet user needs
Page 60: Evidence in Design Decisions
Research Approach for Smartwatch Use in Driving:
Employ crash statistics, literature reviews, naturalistic driving data
Page 61: Evaluation Types and Purposes
Design Evaluation: Test prototypes/systems for usability
Concept Evaluation: Support design principles
Page 62: Three Main Goals of Evaluation
Understanding how to improve design
Diagnosing prototype issues
Verifying performance meets requirements
Page 63: Formative vs. Summative Evaluation
Formative Evaluation:
Focus on iterative improvements and identifying specific user interface problems
Summative Evaluation:
Assess if a design meets benchmarks based on predefined criteria
Page 64: Evaluation Timing
Stages of Evaluations:
Evaluations at design concept, prototype, and product release for effectiveness
Page 65: Methods of Evaluation
Key Approaches:
Literature reviews, heuristic evaluations, cognitive walkthroughs, usability testing
Page 66: Literature Review Purpose
Significance:
Understand current debates and gaps in human factors research
Page 67: Heuristic Evaluations
Conducting Heuristic Evaluations:
Experts evaluate designs based on established principles without user input
Page 68: Heuristic Evaluation Process Steps
Select applicable human factor principles
Inspect designs for heuristic violations
Communicate findings to design team
Page 69: Nielsen's Heuristics for Design
Framework:
Include critical usability principles like visibility, consistency, error prevention
Page 70: Evaluative Methods Recap
Summary of various evaluation techniques used in design
Page 71: Cognitive Walkthrough Method
Similar to heuristic evaluations, focus on usability concerning specific tasks
Page 72: Cognitive Walkthrough Steps
Evaluate usability by considering user task performance and feedback mechanisms
Page 73: Advantages vs. Disadvantages of Expert Reviews
Pros: Quick feedback, early design evaluation
Cons: Requires experienced evaluators, may overlook major issues
Page 74: Usability Testing Overview
Purpose: Assess designs through representative user interactions
Focus on usability metrics and user satisfaction
Page 75: Usability Testing Process
Iterative design and user testing contribute to optimal design selection
Page 76: In-service Evaluation Definition
Scope: Conduct evaluations post-release to assess real-world usability
Page 77: A/B Testing Method
Comparative evaluation of two systems to test minor differences in design
Page 78: Research Methods Categorization
Descriptive vs. Explanatory Research: Illustrate basic vs. applied human factors research
Page 79: Stages of Research Overview
Methodical steps from defining concepts to interpreting experimental results
Page 80: Defining Purpose and Hypotheses in Research
Importance of clarity in research question and expected relationships
Page 81: Exploring Planning in Experiments
Considerations for operationalizing variables and designing observation strategies
Page 82: Hypothesis Testing Overview
Null vs Alternative Hypotheses: Summary of decision-making in statistical testing
Page 83: Experimental Planning Essentials
Key points for preparing and executing empirical studies
Page 84: Measurement Scales in Research
Types: Nominal, Ordinal, Interval, Ratio – each with unique measurement properties
Page 85: Study Designs Considerations
Importance of managing independent variables and avoiding confounds in design
Page 86: Study Designs Summary
Key Types: 1-factor, 2-factor, 3-factor designs to investigate multiple variables
Page 87: Sampling Methodologies
Different designs for participant selection in experiments
Page 88: Representative Sampling Importance
Ensuring participant characteristics mirror the population of interest
Page 89: Probability Sampling Methods
Overview of effective sampling methods to bolstered statistical reliability
Page 90: Non-Probability Sampling Types
Various methods of selecting non-random participants and their implications
Page 91: Specialized Sampling Methods
Detailed descriptions of advanced sampling techniques for research
Page 92: Conducting Studies Steps
Gathering data from initial pilot studies to implement research protocols
Page 93: Data Analysis Procedures
Steps for analyzing research data from descriptive statistics to inferential analysis
Page 94: Conclusions from Data Analysis
Recommendations for generalizing results and understanding validity
Page 95: Limitations in Research
Challenges and inherent issues when conducting behavioral research
Page 96: Challenges in Human Factors Research
Key obstacles such as funding, timing, safety, and ethical considerations