ISWC2002 The Comfort Assessment of Wearable Computers James F. Knight, Chris Baber, Anthony Schwirtz...
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Transcript of ISWC2002 The Comfort Assessment of Wearable Computers James F. Knight, Chris Baber, Anthony Schwirtz...
ISWC2002
The Comfort Assessment of Wearable Computers
James F. Knight, Chris Baber,
Anthony Schwirtz and Huw W. Bristow
ISWC2002
Ergonomics
• Interest in human aspects of wearing technology
• How does the technology affect the human?• Aspects of the technology to assess
• Size• Weight• Positioning
• Need a dependant variable
ISWC2002
Previous work
• Measured responses to musculoskeletal loading
• Body posture and movement
• Problems• Use of specialised
expensive equipment• Need for specialist
knowledge• Time consuming
• Need for quick method of assessment
ISWC2002
Subjective assessment
• Comfort• Discomfort one of the main causes for non-use of
personal protective equipment (Abeysekera & Shahnavaz, 1990; Akbar-Khanzadeh & Biesi,
1995)
• Usually assessed as unidimensional• Wearing something can affect the wearer in
numerous ways• Need a multidimensional tool
ISWC2002
Comfort Descriptors
• Generate terms that describe different elements of comfort based on:
• The concept of wearing something
• Wearing some electrical or mechanical device
• Wearing something that has the ability to measure, record or determine some aspect of the wearer
• 92 terms generated• Need to reduce number of terms
ISWC2002
Comfort Descriptor Matrix
• Eight participants given cards with terms and definitions written on them.
• Participants asked to group the terms based on self selected criteria.
• Term by term association matrix developed.
Accurate data
Aching Adaptation Alignment Amount Annoying Appearance Awkwardness BalanceBlood flow
Blunt hitting
BruisingBumping
intoChafing Change Clamminess
Accurate data - - - - - - - - - - - - - - - -Aching 0 - - - - - - - - - - - - - - -Adaptation 0 0 - - - - - - - - - - - - - -Alignment 2 0 0 - - - - - - - - - - - - -Amount 1 1 1 2 - - - - - - - - - - - -Annoying 0 2 0 0 1 - - - - - - - - - - -Appearance 1 1 0 1 1 3 - - - - - - - - - -Awkwardness 0 0 2 0 0 0 1 - - - - - - - - -Balance 0 0 2 1 0 0 0 5 - - - - - - - -Blood flow 0 4 0 0 0 1 0 0 0 - - - - - - -Blunt hitting 0 3 0 0 0 1 0 0 0 5 - - - - - -Bruising 0 4 0 0 0 1 0 0 0 4 5 - - - - -Bumping into 0 2 1 1 0 2 0 2 2 2 2 2 - - - -Chafing 0 5 0 0 0 1 0 0 0 4 3 6 2 - - -Change 0 1 3 0 0 1 0 4 4 1 1 1 3 1 - -Clamminess 0 6 0 0 0 1 0 1 1 5 3 5 2 4 2 -Clowning 1 1 0 1 1 4 7 1 0 0 0 0 0 0 0 0Cold 0 1 0 1 1 1 0 0 0 3 3 2 1 2 1 1Compensation 1 0 3 1 0 0 1 2 2 0 0 0 1 0 5 0Conscious 1 1 1 1 2 2 3 0 2 0 0 0 0 0 0 0Constricting blood 1 3 0 1 0 0 1 1 1 6 3 2 1 2 1 5Constricting movement 0 1 2 0 1 1 0 1 1 2 2 1 0 1 0 1Cool (fashionable) 0 1 1 0 1 4 6 2 1 0 0 0 0 0 0 0Counteraction 1 0 2 2 0 0 1 1 1 0 0 0 0 0 4 1Cramped 0 0 1 1 1 3 1 2 3 0 0 0 1 0 1 1Damage 4 0 0 2 0 0 1 0 0 0 0 0 0 0 0 0Dangerous 4 0 0 2 0 1 2 0 0 0 0 0 0 0 0 0Difficult 0 0 3 0 0 1 0 6 5 0 0 0 4 0 4 1Digging in 0 3 0 0 0 1 0 0 0 6 6 3 2 3 1 4Dropping 0 0 2 2 1 0 0 1 3 0 1 0 0 0 0 0Embarrassing 1 1 0 1 1 4 7 1 0 0 0 0 0 0 0 0Explosion 4 0 0 2 0 0 1 0 0 0 0 0 0 0 0 0Falling over 2 1 0 1 0 1 2 1 2 1 1 1 3 1 1 1Fit 1 1 0 4 1 1 0 1 2 1 2 1 1 1 2 2Flapping 0 0 1 3 1 0 0 1 2 1 2 0 1 0 0 0Friction 0 1 0 1 0 1 0 0 0 3 3 3 1 3 1 1General fatigue 0 3 0 0 0 2 0 2 1 2 1 2 3 2 2 3Hot 0 1 0 1 1 1 0 0 0 3 3 2 1 2 1 1Impeding activity 0 1 0 0 0 2 0 2 2 1 1 1 3 1 3 2Impeding movement 0 2 0 0 0 2 0 2 2 2 2 1 2 1 4 3Impeding sensation 0 2 1 0 1 1 0 3 3 2 2 1 3 1 4 3Inertia 0 0 1 3 1 0 0 1 2 0 0 0 1 0 0 0Inhibited movement 0 1 0 0 0 1 0 3 2 1 1 1 3 1 3 2Intrusive 1 0 1 0 1 3 1 1 3 0 0 0 0 0 0 0Irritating 0 1 0 0 0 6 2 1 2 1 1 1 1 1 2 2Jerky 0 1 1 0 0 2 0 4 2 1 1 1 4 1 3 1Knocking 0 3 0 1 0 1 0 0 0 5 7 5 2 3 1 3Location 0 1 1 2 1 1 0 1 2 1 1 1 2 1 2 1Loose 1 0 0 3 1 0 1 1 2 0 1 0 1 0 1 1Mental work rate 0 1 2 0 3 2 1 1 2 0 0 0 0 0 0 0Modified movement 0 0 4 0 0 0 0 3 2 0 0 0 1 0 3 0Muscular fatigue 0 5 0 0 1 2 1 2 1 3 3 2 4 2 2 3Obstruction 0 2 1 0 0 1 0 2 2 2 2 1 2 1 3 3Over heating 4 0 0 2 0 0 1 0 0 0 0 0 0 0 0 0
ISWC2002
Multidimensional Scaling• Multidimensional scaling finds
the structure in a set of distance measures between objects or cases.
• Accomplished by assigning observations to specific locations in a conceptual space.
• Distances between points in space match the given dissimilarities.
• By applying the association matrix to MDS 6 groups of comfort terms derived.
ISWC2002
Comfort Groups• Emotion
• Concerns about appearance, embarrassment, conspicuousness
• Attachment• Physical feel of the device on the body
• Harm• Physical affect on the body, damage to the body
• Perceived change• The wearer feels physically different, upset
• Movement• The device affects movement
• Anxiety• Worry about the device, safety and reliability (white coat syndrome)
ISWC2002
Comfort Rating ScalesTitle Endpoints Description
Emotion Low/High I am worried about how I look when I wear this device. I feel tense or on edge because I am wearing the device.
Attachment Low/High I can feel the device on my body. I can feel the device moving.
Harm Low/High The device is causing me some harm. The device is painful to wear.
Perceived change Low/High Wearing the device makes me feel physically different. I feel strange wearing the device.
Movement Low/High The device affects the way I move. The device inhibits or restricts my movement.
Anxiety Low/High I do not feel secure wearing the device.
Emotion
Low High
Attachment
Low High
Harm
Low High
Perceived change
Low High
Movement
Low High
Anxiety
Low High
ISWC2002
SensVest
• Part of the Lab of Tomorrow project.
• Designed to house components that measure and transmit physiological data
• heart rate• temperature• acceleration
• Used as a teaching tool to record aspects of every day activities.
ISWC2002
SensVest Comfort Assessment• Comfort assessment is being
used to evaluate the SensVest
• Comfort measured after carrying out self selected activities
• eg. Walking, sitting, bending, raising and rotating arms
• 10 postgraduate students (age: 252)
ISWC2002
SensVest Comfort Assessment• Comfort measured after
wearing SensVest in accelerometry data collection sessions
• Wrist acceleration during throwing
• Body acceleration during whole body activities
• 14 undergraduates took part in both sessions (age: 19 1)
Wrist acceleration when throwing
-1
0
1
2
3
4
5
0 1 2 3 4 5 6 7 8 9 10
Time (s)
Acc
eler
ati
on
(g
)
Dynamic body acceleration
-2
-1
0
1
2
3
4
0 20 40 60 80 100 120
Time (s)
Acc
eler
ati
on
(g
)
Stand
SitWalk Run
Jump
ISWC2002
SensVest Comfort
• General pattern• Attachment, Perceived
change and Movement scored highest
• Harm and Anxiety scored lowest
• Between conditions• Dynamic condition
scored highest
02468
101214161820
Emotion Attachment Harm PerceivedChange
Movement Anxiety
Comfort Dimension
CR
S S
core
General Throwing Dynamic
ISWC2002
SensVest Comfort• Emotion
• Aesthetics, size and bulk, feel conspicuous
• Attachment• Size, weight, pulls shirt out of shape, move during dynamic activity
• Harm• Not painful, increased during dynamic activity – components collide with the
body
• Perceived change• Size, bulk, due to attachment issues
• Movement• Size, components around shoulder affect arm movement
• Anxiety• Low in general condition (no data collected) increased in accelerometry studies
(data collected)• Dynamic activity – damage to the device
ISWC2002
Redesigned SensVest
• Vest design• Smaller, lighter• Cooler• Can be worn over or
under own shirt• Adjustable size
ISWC2002
Comfort of new SensVest
• Comfort scored when carrying out self selected activities
• CRS scores lowered for new design
• New design improved comfort
02468
101214161820
Emotion Attachment Harm Perceivedchange
Movement Anxiety
Comfort Dimension
CR
S S
core
SensVest Redesigned SensVest
ISWC2002
WECA PC
• Wearable PC that displays different web pages depending on your location.
• Worn in side bag over the shoulder
• Measures 17x4x10cm• Weighs 600g• See Bristow et al.
ISWC2002
WECA PC Comfort
• Comfort assessed under two conditions
• General condition • After carrying out self selected activities
(as used in SensVest study)
• After User trials• Using the WECA PC while walking around the
University of Birmingham campus
• See Bristow et al.
ISWC2002
WECA PC Comfort
• General pattern• Attachment, Perceived
change and movement scored highest
• Harm scored lowest
• Between conditions• Comfort scores
increased in field studies
• Greatest increase in Emotion and Anxiety
02468
101214161820
Emotion Attachment Harm PerceivedChange
Movement Anxiety
Comfort Dimension
CR
S S
core
Laboratory Field
ISWC2002
WECA PC Comfort• Emotion
• Size and bulk, feel conspicuous, increased in social environment
• Attachment• Size and bulk, loose fitting, moves during movement
• Harm• Not painful
• Perceived change• Size, bulk, due to attachment issues
• Movement• Size, position, inhibits arm swing when walking
• Anxiety• Low in general condition (not interacting with device) • High in field study (interacting with device)
ISWC2002
Implications
• Studies show comfort should be measured over a range of dimensions
• Cognitive factors of comfort should be measured
• Comfort should be measured in the field when carrying out a number of activities
• Knowledge of context and situations of use are important
ISWC2002
Conclusions
• CRS provide a tool to assess comfort over a range of dimensions for wearable technology
• CRS can be used to measure comfort specific for device or dimension
• CRS may assist designers decide what aspect of devise needs alteration to improve comfort and make more wearable
• Used pre and post CRS can be used to determine the effectiveness of any modification made to design