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

1. Reduced production output

2. Increased lost time

3. Higher medical costs

4. Increased absenteeism

5. Lower quality of work

6. Higher incidences of injuries and strains

7. Increased likelihood of accidents and errors

8. Increased labor turnover

9. 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

1. Sensing: Information Reception

2. Information Storage

3. Information Processing and Decision Making

4. Action Functions

Page 15: Characteristics of Human-Machine Systems

1. Purposive: Systems have defined goals.

2. Hierarchical: Systems can have hierarchical structure.

3. Environment Dependent: System functions relate to environmental conditions.

4. Functionality: Components serve specific functions towards goals.

5. Interactivity: Components interact with each other.

6. 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

1. Define user population

2. Relevant body dimensions

3. Select design principles

4. Access anthropometric tables

5. Determine population accommodation percentage

6. Account for clothing allowances (optional)

7. 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

1. Define purpose and collect needed data

2. Organize and interpret task data

3. 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

1. Design Evaluation: Test prototypes/systems for usability

2. Concept Evaluation: Support design principles

Page 62: Three Main Goals of Evaluation

1. Understanding how to improve design

2. Diagnosing prototype issues

3. 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

1. Select applicable human factor principles

2. Inspect designs for heuristic violations

3. 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