Exam 2 Flashcards
1
Q
Successful displays consider…
A
task and cognitive capabilities
2
Q
Letter Size - What dimension is most important?
A
Height
3
Q
How do you determine the height of lettering?
A
James Bond Principle
Height >= .007 Radians x Distance
4
Q
PVA
A
Primary Visual Area
Where you look the most?
5
Q
Important things to consider regarding PVA
A
Frequency of Use
Importance of Use
6
Q
4 Categories of Principles of Design
A
Attention
Perception
Memory
Mental Model (expectations)
7
Q
exploit redundancy gain
A
- perception
def: same message expressed more than once in multiple ways
ex. position and hue on stop light
ex. MOA signs place and picture
8
Q
Gestalt Principles of Grouping
A
cues that help us group features or parts into whole objects
9
Q
Gestalt Principles Use in Display Characteristics
A
- keep related tasks in close proximity
- Increase separation between unrelated displays
- similarity causes confusion, highlight similar differences and use different symbols
10
Q
Labeling 4 design criteria
A
Visibility and Legibility
Discriminability
Meaningfulness
Location
11
Q
Labeling Design Criteria: Visibility and Legibility
A
Width of lines and contrast to background needs to be sufficient under poorest expected viewing conditions
12
Q
Labeling Design Criteria: Discriminability
A
Be clear with features that require discrimination
ex. no exit vs exit
13
Q
Labeling Design Criteria: Meaningfulness
A
Keep users in mind and choose icons/labels
Avoid icons/abbreviations that could be confusing
Exploit redundancy gain
14
Q
Labeling Design Criteria: Location
A
Physically close to and unambiguously associated with the entity that they label
15
Q
Parrallax Issues
A
Change in perceived location of an object caused by a change in observer position
ex. misreading the speedometer from the passenger seat
16
Q
Steps in Display Design
A
- Determine users, task, and context of use
2. Determine informational needs and methods to convey info
17
Q
Designing with Color
A
Don’t require people to determine different levels of color (hues)
Color coding should be consistent across a set of displays
Avoid too many colors and highly saturated colors
Use same color to associate similar things (unique stands out)
18
Q
Common use of red in displays
A
Indicate danger of states to be avoided
19
Q
3 Types of Displays
A
Qualitative
Quantitative
Check
20
Q
Qualitative Displays
A
Trend, rate of change, approximation
21
Q
Quantitative Displays
A
Precise numeric value
22
Q
Check Displays
A
Parameters for normal ranges
23
Q
Haptic Feedback Benefits
A
Very fast
Breaks through noise
People like it
24
Q
Limitations to icons/colors for coding
A
International icons and color differences
25
Auditory Message Constraints (use visual if..)
Person Remains in one position
Message doesn't call for immediate action
Complex message
Long message
message will be referred to later
auditory systems already in use
noisy receiving location
26
Contrast
difference in luminance b/w 2 adjacent objects
27
Contrast Sensitivity
min contrast b/w lighter and darker area that can be detected
28
Illuminance
intensity of light falling onto a surface
29
Luminance
light reflecting from a surface
30
reflectance
reflective ability of a surface
31
Fitt's Law Uses
General use: predict movement times
specific example: predict costs of keyboard layouts
32
Fitt's Law Components
Amplitude of the movement
Width of target
Together create the index of difficulty
33
Fitt's Law Implications
Smaller targets increase movement time unless moved closer
Shorter time w/ same amplitude, precision decreases
Greater amplitude increases movement time
Larger target means larger error
SPEED ACCURACY TRADE-OFF
34
HCI
Human Computer Interactions
35
Fitt's Law impact to HCI
Reduce ID (bigger icons, more space)
Compare ID (“capacity” of input devices)
Put things in edges and corners
36
Types of Positioning Controls/Devices
Direct position (touch screen, light pen)
Indirect position (mouse, touch pad)
Indirect velocity (joystick)
Voice
37
Positioning Devices
Use of a control to move an entity such as a cursor to a target
38
Positioning Device Factors to Consider
Feedback of the state of the cursor or entity being moved
Level of Gain required
39
Gain
Change of cursor/change of control position
high gain = small change yields large or fast movement
ideal gain = 1.0-3.0
40
Control-Response Ratio (C/R)
reciprocal of gain
41
Discrete Controls Definition and Applicable Principles
designed primarily for the purpose of activating or changing the discrete state of some systems
Hick-hyman and Fitt's Law
42
Types of discrete controls
Buttons, switches, knobs, levers, keyboard, voice
43
Continuous controls
used for the need to position or point to some entity in space
44
Types of continuous controls
lever, joystick, mouse
45
Accidental Activation Causes
Skill-Based Failures
| Rule-Based Failures
46
Skill-based failures
People inadvertently bump or depress a control
47
Rule-Based Failures
They intentionally activate a control w/o sufficient consideration for the situation
48
Implication and rule of addressing accidental activation
Force people to take more time/exert more effort to complete a task, ease and speed of activation must be balanced with the cost of accidental activation
49
Methods to avoid accidental activation (4)
Locate and Orient
Recess and Shield
Interlock and sequence operations
Resist, delay, and confirm
50
Methods to avoid accidental activation: Locate and Orient
locate and orient the control so it won't be brushed or bumped
51
Methods to avoid accidental activation: Recess and Shield
Physically protect the control from being brushed or bumped
52
Methods to avoid accidental activation: Interlock and sequence
Interlock control so it requires actions in at least 2 directions to activate
Require a specific sequence of actions
53
Methods to avoid accidental activation: Resist, delay, and confirm
require more effort to move the control than expected from bump
use resistance from viscous or coulomb friction and spring-loading to distinguish controls
Require a confirmation of the primary action (ex. OK button when delete file)
54
Card Sorting Use
Evaluate information architecture of a site
55
Card Sorting Method
Conduct some preliminary research
Participants organize topics into categories that make sense to them and help label them
Can use actual cards, pieces of paper, or software
56
Card Sorting Benefits
Understand users' expectation/understanding
Helps you understand and better build the structure of a website, decide what to put on homepage, and label categories/navigation
57
Best Merge Method Definition
graphical depiction of percent of agreement for item grouping based on actual agreement and best merge algorithm
58
Possible Report Structure
Graphical depiction of one possible organization of the items
Organization based upon card sorting and cognitive walk through
59
7 Stages of Action Use
How a user understands what to do and how to accomplish their goals
60
7 Stages of Action Goal Execution
Goals to physical system
Bridge the gulf of execution that is mismatched between users' intentions and actions supported by the software
61
7 Stages of Action 2 basic pieces
Execution
| Evaluation
62
7 Stages of Action Goal Evaluation
Physical system to goals
understand feedback from system after execution is the bridge over the gulf of evaluation
63
7 Stages of Action Creator
Norman
64
7 Stages of Action Components
Execution
1. Establish Goal
2. Form intention
3. Specify action sequence
4. Execute Action
Evaluation
5. Perceiving the system state
6. Interpreting the state
7. Evaluating system state with respect to goals/intentions
65
Usability testing definiton
method of systematically determining the usability of an application
Qualitative and Quantitative assessment of how well a system can be used based on user testing
Done in 1-2 hours x # participants
66
Heuristic Evaluation definition
assessing the usability of an interface based on expertise, existing standards, or guidelines
Done in 1-2 hours
67
Robust Usability Testing Benefits
Methodologically rigorous assessment will enhance the performance of the product/device
Develop an effective, usable product
Identify device failures/difficulties
Rules/regulations don't guarantee a good product
Help bottom line
68
Usability Testing is NOT
Something to do at the end of the product design cycle
Market Research
Way to get opinions about the device
69
Components of Good Usability Testing
Learnability
Efficiency
Lack of Errors
Satisfaction
Usability can vary based on the context in which it is used
70
Components of Good Usability Testing: Learnability
can learn to use product quickly and easily
71
Components of Good Usability Testing: Efficiency
can achieve optimal productivity during use
72
Components of Good Usability Testing: Lack of Errors
errors are not easily committed and cannot be too serious
73
Components of Good Usability Testing: Satisfaction
happy users
74
Stages of Usability Testing
Formative Testing
| Summative Testing
75
Usability Testing Formative Testing
Iterative usability testing performed throughout the development of the device
User input at each stage to guide development
Helps ensure development is on the right track
76
Usability Testing Summative Testing
Testing at the end of the productive design cycle to certify performance is as intended
77
When to do usability testing
as early as possible in design phase
as frequently as possible
before functional specification is complete
when a design decision is made
78
Who to include in usability testing
6-8 participants, 1-2 observers
representatives of the target population
NOT members of design team
79
How to do Usability testing
# Define Usability goals
create/test task scenarios
decide on usability measures
recruit appropriate participants
80
Heuristic Evaluation who to include
Human Factors Expert
1-2 people
81
Usability measures
Success
time to complete tasks
of links/steps to complete tasks/'lostness'
task completion rate/accuracy
user perceptions of ease of use and appeal
user's attraction to the site
eye tracking
overall user satisfaction with the site
82
Planning a Usability Test: Elements of a Test Plan
Scope (indicate what your are testing)
Purpose (identify the concerns, questions, and goals)
Schedule and Location (indicate when and where you will do the test)
Equipment (indicate type of equipment used)
Scenarios (indicate # and types of tasks included in testing)
Subjective Metrics (questions to ask participants)
Quantitative Metrics
Roles (list of staff and roles)
83
Usability Test: Concurrent Think Aloud (CTA)
Understand participants' thoughts as they interact w/ a product by having them think aloud
Encourage a running stream of consciousness as they work
84
Retrospective Think Aloud (RTA)
Moderator asks participants to retrace their steps after completion
Watch video and explain
85
Running a Usability Test: Moderating Techniques
Concurrent Probing
| Retrospective Probing
86
Usability Test: Concurrent Probing
As participant works and does something interesting, ask follow-up questions
87
Usability Test: Retrospective Probing
Wait until end of session to ask questions about thoughts/actions
88
Usability Testing Methodology: Scenario Development
Create effective and realistic scenarios
Requires insight into the subject matter where the device will be used
89
Usability Testing Scenario Recommendations
Test around 5, max 10 tasks
Don't lead/tunnel the user
Start easy, finish hard
Let the user determine when task is completed
90
Pitfalls of Usability Testing
Doesn't guarantee effective software
Fixation on the laboratory environment (artificial, not naturalistic)
91
Benefits of User-centered design
development cost reduced
e-commerce sales improved
product sales increased
employers benefit from easier to use systems
reduced support and maintenance costs
reduced errors
increased safety
92
Local Testing Benefits
less facilitator prep
more controlled setting
participants may engage in more detail/for longer
fewer interruptions and technical issues
93
Remote testing benefits
may reveal more problems under different browsers or connections
easier recruiting
94
Cost-Benefit of Usability Testing
Costs (HF engineer, Mgr, Users)
$$$ HF professional
Benefits:
increased productivity
decreased errors
decreased training
95
Usability Metrics and common tool
Efficiency (time needed to use product to perform tasks)
Effectiveness (performance meets tasks for which it was designed)
Satisfaction/attitude (how do users respond?)
Questionnaires
96
ROI on User Testing (Return of investment)
Reduced long term costs
Increased sales
Increased productivity
Long term user loyalty
97
Usability Metrics: Effectiveness
% task completed
Ratio of successes to failures
number of features or commands to use
98
Usability Metrics: Efficiency
Time to complete a task
time to learn
time spent on errors
% or number of errors
frequency of help or documentation use
99
Usability Metrics: User Satisfaction
rating scale of usefulness
rating scale of satisfaction
number of times user expressed frustration or dissatisfaction
rating scale for users versus computer control of task
perception that the software supports necessary tasks
100
Why is trust in automation important?
Major factor in poor human-automation performance
101
What can trust in automation lead to?
Over-reliance or compliance
102
Trust definition
Expectation that you can rely on or count on someone/something relating to any type of performance or outcome
Willingness of someone to be vulnerable to actions of someone/something else
Reliance (allowing someone/something to do what it should)
103
3 Assumptions for automation
automation is more predictable
automation is superior
automation is easy to deal with (simple)
104
Typical problem in automation
human role is defined by what cannot be automated, not what is needed
105
Machine-centered view
People are:
Vague, disorganized, emotional, illogical
Machines are:
precise, orderly, not distractable, not emotional, logical
106
Human-centered view
People are:
creative, flexible, attentive to change, resourceful, able to make flexible decisions
Machines are:
dumb, rigid, incentive to change, unimaginative, able to make consistent decisions
107
Out of the loop errors
occurs when automation hands off control to user and user isn't paying attention or doesn't know that machine is handing off controls
perception changes when controlling and when monitoring
108
3 sources of failure in automation complacency and intervention
Detection
Situation Awareness
Skill Loss
109
Automation Complacency/Intervention: Detection
more reliable the automation, the rarer the "signal events" become and the poorer the detection
110
Automation Complacency/Intervention: Situation Awareness
people are better aware of dynamic state of processes where they're active participants than passive monitors
111
Generation Effect
People are better aware of the dynamic state of processes in which they are active participants, selecting and executing its actions, than when they are passive monitors of someone (or something) else carrying out those processes
112
Automation Complacency/Intervention: Skill loss
loss of skills an operator experiences by not being an active perceiver, decision maker, or controller
113
Implications of Skill Loss in Automation
Decrease in operators' self-confidence in their own performance (more likely to keep using automation)
May further degrade operator's ability to intervene appropriately should the system fail
114
Automation metaphors definition
relationship between objects and events in a software system and those in a non-computer domain (ex. physical desktop/folders allow better use of operating system)
115
Automation metaphor benefits
support transfer of knowledge from a familiar situation and indicate possible actions in unfamiliar ones
Help users develop an effective mental model
116
Skeumorphs
specific way to convey metaphors and are features of the implementation that are retained in the software implementation
(ex. texture of leather and stitching that may be found on a physical notepad)
117
Sender's 3 Types of Complexity
User complexity
Engineer complexity
technician complexity
118
Sender's 3 Types of Complexity: High User Complexity
User has to do most work and the engineering behind it is limited
technician complexity can range b/w user and engineer
119
Sender's 3 Types of Complexity: Low User Complexity
user has to do little work w/ multiple options, engineering behind it is more advanced and does most of the work
technician complexity lowers as engineer increases
120
Sender's 3 Types of Complexity: General Implication
user-complexity diminishes, engineer-complexity increases. technician-complexity diminishes, engineer complexity increases
121
Anthropometry Definition
scientific study of the measurements and proportions of the human body
122
Anthropometry and Fittting the population importance
fit between an individual and product affects performance and safety
123
Variability in the population comes from..
Age
Gender
Race and Ethnicity
Generations (increasing since the 1920s)
124
Types of anthropometric data
Structural (static measures of body dimensions)
Functional (meausures taken when body is doing some kind of work)
125
Using anthropometric data
Determine users
Determine body dimensions of interest
Determine percent of population that needs to be accomodated
126
Anthropometric design criteria
extremes (min/max allows everyone to be accommodated)
adjustability (accommodate a range of users and fit depends on adjustment)
average (no such thing, most use to save money)
accessibility (doors, elevators, and halls that accommodate wheelchair width/turn radius)
127
General Principles for fitting the data
Clearances should be designed for largest
reaches should be designed for smallest
allow for visibility and normal line of sight
arrange components in functional zones
128
Principles of adjustability
adjust workplace
adjust worker position
adjust work piece
adjust tool
129
Percentile definition
measure used in statistics indicating the value below which a given percentage of observations in a group falls
130
Ergonomics of computer workstations
Shoulders relaxed
Elbows 90 degrees
support lower back
parallel thighs to floor
viewing distance b/w 18-20"
Top of screen at or slightly below eye level
keyboard about elbow height
flat feet on floor
131
2 models of anthropometric dimensions for products
Univariate (required dimensions that consist of one measurement)
multivariate (dimensions w/ more than one measurement)
132
VFT
Virtual Fit Tool
133
Features of the VFT
1. accurately represents the U.S. civilian population
2. allows specification of gender proportions
3. concurrently estimates accommodation on multiple variables
4. user friendly
134
Spine components
24 vertebrae (7 cervical, 12 thoracic, 5 lumbar, sacrum, tailbone)
separated by discs
spinal cord
135
How the back works
muscles of the back and stomach support spine in different postures and create motion
all movements require muscular effort
natural position is s-shaped curve with an inward curve at neck and lower back (lordosis) and outward curve at mid-back (kyphosis)
136
Manual material handling (MMH) injuries root cause (work injuries)
load
number of repetitions
frequency of repetitions
137
Low back compressive forces
MMH injuries = 31% occupational injuries
low back= 71% MMH
25% workers comp costs
Average case = $60,000
138
Factors that affect the likelihood of back injury
amount of twisting in lift (torsion)
lack of stretch breaks
presence of old injuries/scarring
congenital spine defects
aging: osteoporosis
139
NIOSH Lifting Equation Use
lifting equation for calculating a recommended weight limit
140
Reccommended weight limit (RWL)
Weight of load that nearly all healthy workers could perform over a substantial period of time without an increased risk of developing lifting-relating low back pain
141
If RWL @ destination < RWL @ origin one should
eliminate the need for significant control of the object at the destination by redesigning the job or modifying the container/object characteristics
142
Lifting Index definition
relative estimate of physical stress associated with a particular manual lifting task
143
Lifting index calculation
LI = Load weight/RWL
choose lower RWL
144
Design Goal for LI
LI <= 1
145
LI indications of risk
LI > 1 increased risk for some
LI > 3 high risk for most
146
Aerobic Definition
in the presence of oxygen
endurance
walking, bike riding, running
147
Anaerobic Definition
without the presence of oxygen
short, intense activity
sprinting and weight lifting
148
Physiology
Food = fuel
Combustion of fuel takes place with oxygen
Combustion yields energy for mechanical movement
Fueling and cooling system = blood vessels
Blood vessels move supplies (oxygen, carbs, fat derivatives) to combustion sites (muscles and organs)
Blood vessels move byproducts out (lactic acid, CO2, water, heat) for dissipation by skin and lungs
149
Physiological Systems: Respiratory System
Provides oxygen for metabolism and dissipates byproducts
moves air to and from lungs --> Oxygen into bloodstream
removes CO2, water, and heat from blood into air
150
Physiological Systems: Circulatory System
Consists of blood and cardiovascular system
Carries oxygen from lungs to cells that use oxygen
Carries fuel to cells and removes metabolic byproducts
Body's transportation system
151
Physiological Systems: Metabolic System
Supports chemical processes in the body that yield energy
152
Blood
Red blood cells take oxygen to tissue and remove carbon dioxide from them
White blood cells fight germs and infection
Platelets stop bleeding
Plasma is the solution in which blood cells are held
153
Respiration
The volume of air exchanged in the lungs depends on the requirements associated with the work being performed
154
Respiration: Vital Capacity
maximal inspiration
155
Respiration: Residual Capacity
amount of air left when forcing an expiration
156
Respiration: Tidal Volume
Amount of air per breath (liters)
157
Simplified anatomy
Bones (internal framework)
muscles (generate force and movement)
Ligaments (connect bones)
Tendons (connect muscles to bone)
Joints (degrees of freedom to move)
158
Respiration: total capacity
Vital capacity + Residual Capacity
159
Work Capacity
Max rate of energy production during physical work, increases with the duration of the work
Most blood to muscles and least to bone and fatty tissue
160
Metabolic system Definition
energy yielding system
161
Energy inputs
food and drink (nutrients)
162
Basal metabolism
energy to function
163
resting metabolism
without work
164
work metabolism
due to addtional energy needed to work
165
muscle types
cardiac (heart)
smooth (digestive, not under control)
skeletal (under control)
166
muscle components
muscle fibers
167
Display Design: Perceptual Principles (Know 1-2)
1. Make displays legible (contrast, visual angle, illumination)
2. Avoid absolute judgement limit
3. Top-down processing means that either display consistent with expectations or make signal much stronger to make sure it's interpreted correctly
4. Redundancy Gain
5. Similarity causes confusion,use discriminable objects
168
Display Design: Mental Model Principles (Know 1-2)
6. Pictorial Realism (display looks like variable it represents)
7. Principle of moving parts (moving elements of a dynamic display should move in a consistent patter to users' mental models)
169
Display Design: Attention Principles (Know 1-2)
8. Minimize info access cost (min moving attention b/w displays, keep organized to mental models)
9. Proximity compatibility (keep similar tasks together to ease attention costs)
10. Principles of multiple resources (use visual and auditory signals/info)
170
Display Design: Memory Principles (Know 1-2)
11. Replace memory with visual info/knowledge in the world
12. Use predictive displays if you can show what will happen in system
13. Be consistent (similar displays require similar interpretation)
171
Control Coding: Shape
Powerful
can make natural mappings more powerful
doesn't require visual cues
172
Control Coding: Labeling
Better as redundant code
173
Control coding: Mode of Operatoin
how the control works tells you what it's used for
ex. amount of force should indicate use
174
Discrete Controls: Attention (know 1-2)
1. Proximity
| 2. Avoid resource competition
175
Discrete Controls: Perception (know 1-2)
3. Make accessible
| 4. Make discriminable
176
Discrete Controls: Perception (know 1-2)
5. Exploit redundancy gain
| 6. Avoid judgement limits
177
Discrete Controls: Memory (know 1-2)
7. Knowledge in the world
| 8. Be consistent
178
Discrete Controls: Mental Model (know 1-2)
9. Location compatibility
| 10. Movement compatibility
179
Chinese and American Different Color perceptions
cold: white (c) vs blue (a)
on: green (c) vs red (a)
180
Speed-accuracy tradeoff
fast, accuracy suffers
accurate, speed suffers
Hick-hyman law and decision complexity
181
GOMS
Goals
Operators (actions)
Methods (sequences)
Selection Rules (what methods to be used in each goal)
182
Schneiderman's Principles of Good Design (know 2-3)
1. consistency
2. universal usability
3. information feedback
4. design dialong to yield closure
6. Permit easy reversal of actions
7. Support internal locus of control
8. Reduce short term memory load
183
QUIS definition and advantages and disadvantages
Questionnaire for User Interface satisfaction
+
easy to use and learn
reliable and valid
easily modifiable
-
used only in analysis of HCI devices
representative user sample required
$$$
184
SUS definition def and benefits
System Usability Survey
Quick and dirty measurement
low-cost usability scale for global assessments
reliable, used to make comparisons of user performance changes b/w versions
10-item likert scale
185
Acquisition Automation
Sensing and registration of of input data (highlighting, filtering, warnings)
ex. radar
186
Information analysis automation
takes input data and analyzes it in some way
select decision
execute task
187
General criteria for functional allocation of automation
designed to work in conjunction w/ humans controlling it NOT expecting human to accommodate the automation
188
Human-centered automation design principles
better feedback, visibility, and transparency
better cooperation
flexible or adaptive automation
better matching of designs to mental models
allow human to be in control and have trust in and support human capabilities
189
Trust is nonlinear: factors
negative experiences weigh more
initial experiences weigh more
low reliability --> rapidly declining trust
higher predictability is important
190
Guides for lifting
1. Plan lift
2. find best lifting technique (squat better)
3. get secure grip
4. pull load close in
5. alternate task: lifting vs sitting
