1536-1268/03/$17.00 © 2003 IEEE ■ Published by the IEEE CS and IEEE ComSoc PERVASIVEcomputing 19

Editor: Thad E. Starner ■ Georgia Institute of Technology ■ thad@cc.gatech.edu

Wearable Computing

W hen we as developers and de-signers create a system that

requires user interaction—whether it iscomputer software, a kitchen appli-ance, or a door knob—we often fall vic-tim to a common mistake: we use our-selves as the model for our system’spotential users. Even developing for an“average user” is a pitfall that resultsin numerous users whose needs areoverlooked. The average user mightaccount for the largest spike under abell curve, but nonaverage users ac-count for a much larger percentage ofthe general population. Additionally,the number of people possessing all ofthe average attributes being consideredin a design is very small. So, the design-ers’ goal should be to broaden the sec-tion of the bell curve that their systemtargets. This concept is called universaldesign, and it’s especially important inwearable computing because using asystem while mobile and while in dif-ferent environments can have a majoreffect on its usability.

SIMILARITIES IN MOBILITYAND DISABILITY

Universal design attempts to createproducts that are as usable as possibleby as many people as possible, regard-less of age, ability, or situation.1 Notonly are such designs more accessibleto people with disabilities, they are alsomore usable and functional for all users.For example, a system designed for ablind user shares similar attributes witha system designed for a user who is driv-

ing a car and cannot look at a screen.A system designed for a deaf user willalso be useful to a person using the sys-tem in a noisy restaurant. Similarly, awearable computer user attempting tocontrol a graphical user interface whilewalking has much in common with anolder user with low vision and low dex-terity. Special concerns about user lim-itations exist for wearable devices thatwill be used in environments that thedesigner might not anticipate.

UNIVERSAL DESIGN INSPIRESINNOVATION

The practice of universal design hasresulted in many products originallyintended for the disabled population thatbenefit everyone—closed captioning,books on tape, and even the telephone,for example. Conversely, sometimes aproduct’s designers don’t anticipate thelarge market their device will haveamong the disabled community. TheRIM Blackberry, a wireless handheldthat can send and receive email and textmessages, has become hugely popular inthe deaf community because it lets peo-ple who might not be able to speak on acell phone have mobile communicationaccess. In many senses, some of the firstwearables were designed for communi-ties with special needs. For example, in1968, Hubert Upton describes a displayin a pair of eyeglasses to aid in lipread-ing,2 and in 1977 C.C. Collins describesa tactile system for assisting the blind infinding their way.3 The “Universal Re-mote Console Design”and “Mobile

One-Way Sign Language Translator”sidebars describe current efforts in cre-ating enabling technology.

WEARABLES AS UNIVERSALTRANSLATORS

Although universal design generallytries to accommodate as many differ-ent users as possible, making devicesthat all people can access at all timesisn’t always possible. Imagine a hypo-thetical ATM that all users can accessregardless of ability. The result wouldbe an unusable device with a cacoph-ony of sounds, graphics, and I/O rang-ing from eye-tracking to haptics.Another approach, which is particu-larly interesting to the wearablescommunity, is to have users bring theirown tailored interfaces to each publicsystem. This concept is often knownas an alternate user interface and couldtake the form of a cell phone, PDA, orwearable computer that lets the userhave personalized input, control, anddisplay mechanisms while maintainingan awareness of his or her preferencesand characteristics.

A key requirement for realizing thesealternative interfaces is a standard proto-col that lets the user’s control device andthe public system communicate. Currently,the International Committee for Infor-mation Technology Standards (the V2committee) is charged with developing anational standard for an Alternative Inter-face Access Protocol (see www.v2access.org). The AIAP’s goal is to complementand build on industry activity in home net-

Universal Design: Lessonsfor Wearable ComputingMaribeth Gandy, David Ross, and Thad E. Starner

working, wireless networking, and meta-data registries for discovery and interop-eration of devices. Obviously, implement-ing this standard will benefit not onlypersons with disabilities but all users.

THE SEVEN PRINCIPLES OFUNIVERSAL DESIGN

The Seven Principles of UniversalDesign are guidelines developed at theCenter for universal design at North Car-

olina State University in collaborationwith a consortium of universal designresearchers and practitioners from acrossthe US.1 These principles can help guide adesign process, ensuring not only that theresulting system considers as much of auser population as possible, but also thatit incorporates features that will increasethe system’s general usability. The AIAPstandard demonstrates a different ap-proach to universal design, where the tar-

get system does not attempt to meet theneeds of all users but lets users tailor it totheir abilities. So, an interesting exercise isto use the hypothetical design of an AIAP-enabled mobile device to illustrate theSeven Principles of Universal Design.

1. Equitable use: The design is useful andmarketable to people with diverse abili-ties. This is an AIAP device’s key featurebecause it can take any form appropriate

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Gregg Vanderheiden, director of the Trace Research Institute (www.

tracecenter.org) at the University of Wisconsin has advocated universal

access to information systems since the early 1990s.1 When the late

Ron Mace, founder and program director for the Center for Universal

Design at North Carolina State University, defined universal design in

1991 as “an approach to creating environments and products that are

usable by all people to the greatest extent possible,”2 he had architec-

tural building design in mind. When Vanderheiden joined a national

team Mace headed in 1995 to define universal design principles, he

already recognized the importance of applying those principles to

designing information appliances. Universal design principles were

thus conceptualized as fully relevant to designing mass-marketed con-

sumer appliances:

“A good universal design is a commerciallypractical, mass-market design that is usable by andattractive to the maximum possible number anddiversity of users—given the best of today’s collectiveknowledge, technologies and materials.”3

Vanderheiden also understood that it was unreasonable to require

manufacturers of consumer products—from thermostats to micro-

wave ovens—to design interfaces into each of their products and

models that could meet the diverse needs of people with disabilities.

Instead, he realized it was more practical to devise a universal remote

console that could provide easy access to a wide range of products.

Clearly, it was more economical to design one specialized interface

that each user could customize to meet his or her needs than to

build such an interface into every appliance the person might need

or encounter. Of course, to realize this goal, a universal remote com-

munications protocol had to be established. This is now called the V2

standard, and it was designed from the beginning using universal

design criteria.

Once V2 is fully established and implemented in consumer products

and appliances, universal remote consoles will let most disabled people

easily access consumer appliances that would otherwise be inaccessi-

ble. So, this one remote control device would let people with disabili-

ties buy and use almost any mass-produced appliance at a mass con-

sumer price, instead of paying two to five times more for specially

adapted appliances. Further, if this remote console is small enough to

carry in a pocket or purse, it could enable access to information kiosks,

Internet kiosks, ATMs, transit system fare machines, and more.

Initially, a Trace research team envisioned a device about the size of a

deck of cards but soon realized that constructing a console this size

would be difficult. After creating an initial prototype that was some-

what larger, they began focusing more on adapting existing hardware

to this purpose. Candidate hardware included palm-top computers,

wearable computers, PDAs, and even cell phones. The challenge was

to adapt and program this hardware to best meet universal design cri-

teria so that simple and intuitive input and output could occur across

multiple disabled populations, and users could adjust the device to

best suit their individual abilities. To date, this includes output

“displays” that employ large print and enlarged graphic presentation,

and speech output. This system has been implemented in an iPAQ

Pocket PC. Input controls are still a concern, however, because a per-

son with vision loss cannot effectively use a touch screen, and the navi-

gation buttons on an iPAQ might be difficult for some to use.

Trace Center engineers have more recently developed a prototype

remote console voting tablet that better addresses some of these input

issues. However, work must still be done in this area. In terms of wear-

able computers, a research team at the Atlanta Veteran’s Administra-

tion Rehab Research and Development Center is currently using uni-

versal design criteria to develop a wearable computer with both voice

and keypad input capability, and speech and tactile output.

REFERENCES

1. G. Vanderheiden and K. Vanderheiden, Accessible Design of Consumer Prod-ucts: Guidelines for the Design of Consumer Products to Increase their Accessibil-ity to People with Disabilities or Who Are Aging, tech. report, Trace Researchand Development Center, 1991.

2. R. Mace, G. Hardie, and J. Plaice, “Accessible Environments: Toward Uni-versal Design,” Design Interventions: Toward A More Humane Architecture,Preiser, Vischer, and White, eds., Van Nostrand Reinhold, 1991.

3. G. Vanderheiden, “Universal Design Definition,” Uaccess-l archive, 17 Oct.1995, http://trace.wisc.edu:8080/mailarchive/uaccess-l.

UNIVERSAL REMOTE CONSOLE DESIGN

for the user. One person might have asophisticated system integrated into hisor her wheelchair that uses eye trackingfor control, while another might prefera cell phone with a headset for voice con-trol and audio display. So, all users canaccess the ideal interface for their needs.

2. Flexibility in use: The design accom-modates a wide range of individual pref-erences and abilities. Although users canpersonalize an AIAP device, designersmust still consider flexibility. Wheninteractions will occur in a mobile envi-ronment especially, the user’s interactionneeds could vary, and the device mustallow for this flexibility. For example,the user might normally prefer audio dis-play except when he or she has privacyconcerns in a crowd. In this case, a dis-

crete graphical display of informationon a head-mounted display would bepreferable.

3. Simple and intuitive: The design is easyto understand, regardless of the user’sexperience, knowledge, language skills,or current concentration level. This prin-ciple is the goal of all interactive systemsbut achieving it can be difficult. A sim-ple and intuitive interface is especiallyimportant in a mobile setting, where theuser might be focusing on other tasks.Designers must also consider cognitiveimpairments when developing a devicefor the disabled population. Thedesigner must be aware of the limitationsof memory, recognition, and under-standing that can accompany variouscognitive disabilities.

4. Perceptible information: The designcommunicates necessary informationeffectively to the user, regardless of ambi-ent conditions or the user’s sensory abil-ities. For a system to be effective, a usermust be able to comprehend its state.Again, in a mobile environment, ensur-ing that the user is receiving the neces-sary feedback from the device can be dif-ficult. The user might miss the iconshowing an error if he or she is drivinga car or concentrating on crossing thestreet. A common problem with currentmobile devices is their reliance on onlyone output mode for important infor-mation, thus making them unusable bypeople with disabilities. For example,cell phones often rely heavily on visualdisplays for output and use, makingthem inaccessible to blind users.

WEARABLE COMPUTING

JULY–SEPTEMBER 2003 PERVASIVEcomputing 21

For the deaf community in the US, apartment hunting, communi-

cating with a doctor, or even getting directions at the airport can be

inconvenient and intimidating. Very few fellow travelers, landlords, or

doctors “speak” American Sign Language, which is distinct from Eng-

lish with its own grammar, vocabulary, and visual puns.

One possible way for the deaf to communicate with the hearing

is through writing. However, writing limits conversation to around

15 words per minute

(both spoken and

signed conversations

are normally around

150 wpm). Addition-

ally, many native

signers have difficulty

generating English

text because English

is a second language

for them (recognizing

a given English

phrase is easier).

Georgia Tech is

attempting to create

a one-way translator

for American Sign

Language. The signer

is limited to com-

mon phrases and

queries that

require simple responses, such as nodding yes or no, holding up a

number of fingers, or pointing. For example, while interacting with

a landlord, an apartment seeker might sign the equivalent of “How

many bedrooms does the apartment have?” The system translates

the utterance to English, shows it to the signer on her display for

approval, and then speaks it to the landlord. The landlord then res-

ponds by holding up two fingers to indicate that the apartment has

two bedrooms.

Figure A shows the current prototype hardware. A camera

mounted in the cap’s bill watches the signer’s hands. Accelerome-

ters worn on wrist bands provide additional features for sign

recognition. A CharmIT Pro wearable computer executes the sign

recognition software, and the signer views the potential English

translations on a MicroOptical head-up display. A speaker in the

cap announces the selected English phrase.1,2

Our translator is limited in its scope, similar to the tasks addressed

by the early speech recognition community. Yet, if we can demon-

strate our approach’s feasibility, we might interest other researchers

in the field.

REFERENCES

1. H. Brashear and T. Starner, “Using Multiple Sensors for Mobile Sign Lan-guage Recognition,” IEEE International Symp. Wearable Computing, sub-mitted for publication.

2. T. Starner, J. Weaver, and A. Pentland, “Real-Time American Sign LanguageRecognition Using Desk and Wearable Computer-Based Video,” IEEE Trans.Pattern Analysis and Machine Intelligence, vol. 20, no. 10, Dec. 1998, pp.1371–1375.

MOBILE ONE-WAY SIGN LANGUAGE TRANSLATOR

Figure A. Prototype of an American SignLanguage recognition apparatus.

5. Tolerance for error: Thedesign minimizes hazards andthe adverse consequences ofaccidental or unintendedactions. Designers must al-ways allow for easy recoveryor error avoidance in an inter-active system. In a mobile en-vironment, error tolerance iseven more important becausethe incidence of error willincrease due to environmen-tal factors and changing focusof attention. With the AIAPdevice, the user might beinteracting with critical sys-tems, such as an ATM, wherea poor error tolerance couldcause serious consequences.The ideal solution keeps theuser from making errors byproviding a simple and intu-itive system, but the systemmust at least allow for easyrecovery from inevitable usermistakes.

6. Low physical effort: Thedesign can be used efficientlyand comfortably with minimum fatigue.A device’s necessary physical require-ments certainly factor in when a tar-get user could suffer from impaireddexterity. For example, an elderly usermight have trouble depressing buttonsthat require excessive force. In wear-able computing, physical effort isalways an issue when devices might re-quire the user to wear equipment oruse an interface that can be fatiguingor require excessive strength and dex-terity. When designing a product suchas an AIAP device, the developer mustevaluate the required physical effortfor carrying and interacting with thesystem throughout the day in varioussituations (carrying groceries, climb-ing stairs, or walking the dog, forexample).

7. Size and space for approach and use:The design provides appropriate size andspace regardless of users’ body size, pos-

ture, or mobility. One problem with try-ing to make systems such as ATMsaccessible to everyone is the size andspace issue. Often these public devicesare too high for a user in a wheelchairor too low for a tall person, or perhapsthe space around the system is difficultfor a user with a walker to navigate.Letting users access these public sys-tems from their own portable devicesoffers an easy solution to the problemsinduced by system placement and allot-ted physical space.

T he universal design principles wediscuss hint at how wearable com-

puters might address disabled popula-tions’ needs. At the same time, theseven principles also provide usefulguidelines on how wearable computerinterface designers can broaden theirsystems’ appeal in the general popula-tion. Perhaps if we are very fortunate,

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ISWC—7th IEEE International Symposium on Wearable Computers21–23 October

White Plains, N.Y.

http://iswc.net

Ubicomp–5th International Conference onUbiquitous Computing12–15 October

Seattle, Wash.

www.ubicomp.org

ICMI-PUI—5th International Conference on Multimodal Interfaces and Perceptual UserInterfaces5–7 November

Vancouver, B.C.

http://icmi.cs.ucsb.edu

UIST—16th ACM Symposium on User InterfaceSoftware and Technology 2–5 November

Vancouver, B.C.

www.acm.org/uist

UPCOMING CONFERENCES

Tomorrow'sPCs,handhelds, andInternet will usetechnology thatexploits current research inartificial intelligence.Breakthroughs in areas suchas intelligent agents, theSemantic Web, data mining,and natural languageprocessing will revolutionizeyour work and leisureactivities. Read about thisresearch as it happens in IEEE Intelligent Systems.

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SEE THEFUTURE OFCOMPUTING

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our pursuit of better interfaces willlead to a device with mass appeal, aswith Alexander Graham Bell’s inven-tion of the telephone while pursuingthe concept of a hearing aid for hisdeaf wife.

REFERENCES

1. The Center for Universal Design, “The Prin-ciples of Universal Design, Version 2.0,”North Carolina State Univ., 1997; www.design.ncsu.edu:8120/cud/univ_design/princ_overview.htm.

2. H. Upton, “Wearable Eyeglass Speechread-ing Aid,” Am. Annals of the Deaf, vol. 113,Mar. 1968, pp. 222–229.

3. C.C. Collins, L. Scadden, and A. Alden,“Mobility Studies with a Tactile ImagingDevice,” 4th Conf. Systems and Devicesfor the Disabled, 1977.

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next issue

Maribeth Gandy is a re-

search scientist with the

Interactive Media Technol-

ogy Center at Georgia Tech,

where she has worked as a

student or full-time faculty

member since 1998. Con-

tact her at maribeth.gandy@imtc.gatech.edu.

David Ross is a rehabilitation

research engineer at the

Atlanta Veteran’s Adminis-

tration Rehab Research and

Development Center. Con-

tact him at davidross1@

mindspring.com.

Thad E. Starner is an assistant professor of com-

puting at the Georgia Institute of Technology,

where he directs the Contextual Computing

Group in the Institute’s College of Computing.

Contact him at thad@cc.gatech.edu.