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.

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 Scales

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: 25  2)

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)

ISWC2002 SensVest Comfort General pattern Attachment, Perceived change and Movement scored highest Harm and Anxiety scored lowest Between conditions Dynamic condition scored highest

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

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

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