Final Flashcards
Three main reasons for human factors engineering.
Safety, Performance, Satisfaction
HF Design Process
Create Evaluate Understand
Task Design
Changing what operators do
Equipment Design
Changing equipment people work with
Environmental Design
Changing environment where work is done
Training
Enhancing knowledge and skills
Selection
Picking people suited for the task
Team and organization design
Group communication and organizational climate
Systems Thinking
Interconnection, adaptation, environment
UI
Design of GUI
UX
GUI and user interaction with the system
System Design Processes
VEE, Plan-Do-Check-Act-Cycle, Scrum
Independent variables
Variables being changed
Dependent variables
Variables to be studied
Confounding variables
Outside influences on results
Within-subject
All subjects receive all levels of IV
Between-subject
Every level of IV has different subjects
Type I error =
False positive
Type II error =
False-negative
p-values issues
Forces binary thinking, not representative of effect size
p-value alternatives
Confidence intervals, effect sizes, Bayestian
Luminance vs brightness
Luminance is the intensity of photons, brightness is the perceived amount of light
Fovea
The central area of the eye is almost exclusively of cones
Cones
Perceive color
Rods
Perceive BW and brightness
Ciliary body
Muscles that adjust the lens
Order of cones by wavelength
S (blue), M (green), L (red)
Top-down processing
Experience and knowledge
Bottom-up processing
Stimulus from the words
Signal Detection Theory
Hit | False Alarm
______|________________
Miss |Correct reject
Ways to improve ROC curve
Different discrimination, sensitivity
Affordances
Possible interactions between user and object
Gestalt Grouping types
Proximity, similarity, continuity, symmetry, area, closure
Common fate
Items moving together will be perceived as a unit
Figure ground
People perceive items as in the foreground or in the background
Sound envelope
Attack, sustain, decay
Timbre
Fundamental frequency and multiple harmonics
Malleus, Incus, Stapes
Middle ear bones
Cochlea
Made up of organ of corti
Organ of corti
Lots of little hairs moved by membrane that generate electrical signals
Loudness
Perception of sound intensity
Temporary Threshold Shift
Ears temporarily attenuate sounds when in loud environment, takes time to recover
Just noticeable difference (Weber’s Law)
K= Constant, delta I= Change in intensity, I = Absolute level of intensity
Alarm principles
Heard over background, avoid excessive intensity, Should not startle, doesn’t disrupt processing of other signals, Is information and not confusing
Vestibular System
Used for balance
Motion sickness
Comes from a disconnect between vestibular system and movement
Cognitive bandwidth
How quickly environment changes
Cognitive Familiarity
How often and for how long a person has experienced an environment
Cognitive knowledge in the world
Extent information is indicated by features in the environment
Human Information Processing
How resources are allocated between sensing, perception, cognition, response
SEEV
Salience, Effort, Expectancy, Value
Perception formula
S-Ef+Ex+V
WM types
Visuospatial sketchpad, Phonological loop, episodic buffer
LTM types
Semantic/declarative, episodic, procedural
Multiple Resource Theory
Mind has limited resources for processing. Different modalities can have different levels.
Interruption lag
Time required from old task until new task
Fluency of return
Rate that new task full attention is gained
System 1
Skill based, intuitive, Normative and Descriptive DM, more proficient
System 2
Knowledge based, analytic, Heuristics and Biases, less proficient
Decision making stages
Acquire and integrate, interpret and asses, plan and choose, monitor and correct
SA
Perception of elements in environment, comprehension of meaning, projection of their status in near future
Fitts Law
Response time predicted by distance between inputs and size of target
Automation OOTLUF
Poor detection, poor situation, skill lose when using automation
Link analysis
Study of movement between inputs
Joint types
Synovial- no tissue between joins
Fibrous- Connecting bones of skull with fibrous tissue
Cartilaginous- Intervertebral discs
NIOSH Lifting Equation
RWL= LC * HM * VM* DM * AM * FM * CM
LC: Load Constant
HM: Horizontal Multiplier
VM: Vertical Multiplier
DM: Distance Multiplier
AM: Asymmetric Multiplier
FM: Multiplier
CM: Coupling Multiplier
Lifting Index
> 3 high risk for low back injury
Muscle types
Smooth, cardiac, skeletal
Rechargeable battery energy
ATP
Lactic acid
Generated by anaerobic exercise
Conversion ratio of chemical energy
20% muscular work
80% heat
Blood components
Red blood cells, white blood cells, plasma
Body fatigue over 8 hours if ______% of max aerobic capacity
30-40%
Stressors
Environment, Physiological Arousal, Health, Experience
Environmental stressors
Motion, temperature, air quality
Psychological stressors
Cognitive appraisal, level of arousal
Affects of overarousal
Cognitive tunneling, WM loss, Strategic shifts
Workload
Time required/time available. Should be < .8
Workload measurement
Primary task measures, secondary task performance, loading tasks, physiological measures, subjective measures
Origin of workman’s comp
Triangle shirtwaist factory fire
Workman’s comp
Provide income and medical benefits, reduce court delays and costs, eliminate lawyer costs and trials/appeals, encourage employer interest in safety, promote study of accident causes
OHSA vs NIOSH
OSHA pubs industry standards, NIOSH makes recommendations to OSHA
Accident predictors
Age, gender, experience, stress/fatigue, job characteristics, illumination, noise and vibration, temperature and humidity
Unintended erros
Slips, lapse
Intended errors
Knowledge-based mistake, Rule-based mistake, violation
Sign considerations
Convery seriousness, describe hazard, hazard consequences, behavior to avoid
Motivation potential
TI: Task identity
SV: Skill variety
TS: Task significant
A: Autonomy
F: Feedback
Performance support systems
On job training.
Cognitive load theory
Learner attention divided by Intrinsic load (Workload imposed by task to be learned), Germane Load (Demand for resources necessary to learn task), Extraneous Load (Unrelated demands)
Complexity
Feedback loops, interconnected subsystems, unexpected interactions
Coupling
Tight connection between subsystems, something affecting one impacts another
