EDITORS: Kristof Van Laerhoven, kvl@eti.uni-siegen.de
Oliver Amft, oliver.amft@fau.de

DEPARTMENT: WEARABLE COMPUTING

25 Years of ISWC
Time Flies When You’re Having Fun
Tom Martin, Virginia Tech, Blacksburg, VA, 24061, USA

Thad Starner, Georgia Institute of Technology, Atlanta, GA, 30332, USA
Dan Siewiorek, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
Kai Kunze, Keio University, Tokyo, 108-8345, Japan
Kristof Van Laerhoven, University of Siegen, 57076 Siegen, GermanyM

UCH has changed in the landscape of wearables research since the ﬁrst International
Symposium on Wearable Computers (ISWC)
was organized in 1997. The authors, many of whom wereactive in this community since the beginning, reﬂect now
25 years later on the role of the conference, emerging
research methods, the devices, and ideas that have stood
the test of time—such as ﬁtness/health sensors or augmented reality devices—as well as the ones that can be
expected still to come, like everyday head-worn displays.
Wearables research used to revolve around labgrown prototypes that were often created fromscratch by young PhD students that experimented
with small and modular hardware components, imagining new user-centered applications. Fast forward to
2009: iOS and Android touchscreen smartphones arecommonplace, with over 100M being sold each year,
equipped with applications similar to those prototyped more than a decade earlier, such as contextbased web search and navigation; smartphones havebecome indispensable. What else has changed in thisresearch community? Time for a look back at the past
two and a half decades.

AN EVOLUTION IN RESEARCH
PRACTICESAs research into wearable systems has grown andevolved, several trends have emerged in how

1536-1268 ß 2021 IEEE
Digital Object Identiﬁer 10.1109/MPRV.2021.3094898
Date of current version 30 July 2021.

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researchers adopt new processes to create new wearable systems and applications. A methodology thathas served the ISWC community well these 25 years iscalled time travel: Individual researchers decide what
functionality they want; implement it as best as possible; experiment; and then iterate.

From Roll Your Own Hardware to Apps
Wearable computers were such a new hardware concept in the early days that researchers with a wearable vision had to prototype their own systems, often
from scratch and with themselves as a primary user.
Focus was on dealing with computers’ limited working memories, processing power, and battery charge.
As just one example, CMU’s Navigator 1 wearable
computer, shown in Figure 1, was developed in 1992–
1993 for two applications: a campus tour guide andan aircraft wiring harness manufacturing tool. The
Navigator 1 hardware included GPS to gather location data, sound processing to support continuous
speech recognition, a head mounted display to provide feedback, and an analog cell phone for wirelesscommunication.4 Meeting the expected battery lifeof eight hours for the manufacturing application was
difﬁcult given the available hardware and software at
the time. Today’s commonplace, high-energy density
lithium-ion batteries were not yet commercially available, so the ﬁnal design used two lead-acid batteries,
which accounted for nearly six pounds of the system’s eight pound weight (and that heavy weightrequired a custom fabric harness from a local backpack maker to be wearable). Low power hardware
intended for mobile systems was difﬁcult if not
impossible to ﬁnd off-the-shelf. For example, thePublished by the IEEE Computer Society

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WEARABLE COMPUTINGFIGURE 1. The VuMan and Navigator wearable computers, circa 1991–1995.

Navigator 1’s sound processing board was intended
to be used in a desktop personal computer; unnecessary hardware was desoldered from the board tosave power. More dramatic power savings were available by modifying the Unix-based operating system
to halt the CPU during the OS’s idle loop and to put
the spinning hard drive in standby mode when thedrive was not being used. The combination of hardware and software changes to lower the power consumption nearly tripled the battery life. Within a few
years, power management features such as thesewould become commonplace in off-the-shelf hardware and software, but at the time, they had to be
designed and implemented from scratch.
Starting in the 2000s, steadily increasing attention
from industry in wearable and portable devices has
spawned smaller, lower power, and interchangeable
components. Furthermore, many of these components
were also higher performance than earlier versions,thus more complex and compelling wearable computing applications could be developed in a smaller form
factor with less weight and a longer battery life. One
concrete example of this trend is that the speech recognition software for the Navigator 1 took about ten
times talk-time to process speech, e.g., one second of

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speech took about ten seconds to process. Within
about ﬁve years, that speech recognition software wasported to the Itsy handheld computer, where the software ran in less than talk-time—and the Itsy ﬁt in thepalm of the user’s hand and was powered by two AAA
alkaline batteries.2 Much of these essential hardware
components of the early wearable systems have now
been integrated in smartphones and smartwatches,allowing research to increasingly build new wearable
functionalities through software and Apps.

CONCEPTS THAT STOOD THE TESTOF TIMEBy wearing their own hardware, researchers could “livein the future” and explore both the promise and thechallenges of mobile technologies before they became
commonplace. Which research strands have growninto products and research communities? In the following, we list the ones that stand out to us.

Augmented Reality
One of the intended applications of the Navigator 1 was amanufacturing application for aircraft wiring harnesses
for Boeing, which assisted workers by overlaying

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WEARABLE COMPUTINGVISIONARY WEARABLES RESEARCH
Augmented Reality: Early example of smartphone AR

Symp. Wearable Comput., 2002, pp. 133–134, doi:

and use of QR-style codes.
[SB1] D. Wagner and D. Schmalstieg, “First Steps

10.1109/ISWC.2002.1167230.
[SB7] C. Narayanaswami and M. T. Raghunath,

Towards Handheld Augmented Reality,” in Proc. 7th IEEE

“Application design for a smart watch with a highInt. Symp. Wearable Comput., 2003, pp. 127–135, doi:

resolution display,” in Proc. 4th Int. Symp. Wearable

10.1109/ISWC.2003.1241402

Comput, 2000, pp. 7–14, doi: 10.1109/ISWC.2000.888452.
Wireless Personal Area Networks: ISWC

Task Guidance: Inspection, maintenance, and repair
were identiﬁed early as tasks where wearables might
help guide the user.

[SB8] R. F. Heile, “Solutions for the last 10 meters: an[SB2] L. J. Najjar, J. C. Thompson, and J. J. Ockerman,“A wearable computer for quality assurance inspectors

overview of IEEE 802.15 working group on wpans,” inProc. 3rd Int. Symp. Wearable Comput, 1999, Art. no. 10,

in a food processing plant,” in Proc. 1st Int. Symp.

doi: 10.1109/ISWC.1999.806636.

Wearable Comput., 1997, pp. 163–164, doi: 10.1109/
ISWC.1997.629935.
Remote Collaboration: Enabling a remote expert tohelp a local worker.
[SB3] M. Bauer, T. Heiber, G. Kortuem, and Z. Segall,“A collaborative wearable system with remote sensing,”
in Proc. 2nd Int. Symp. Wearable Comput., 1998, pp. 10–17, doi: 10.1109/ISWC.1998.729524.
Context Awareness: Forerunners to Google Lens andannotating of phones’ photos with location or notes.
[SB4] T. Starner, B. Schiele and A. Pentland, “Visualcontextual awareness in wearable computing,” in Proc.

E-Textiles: A clothing liner with integrated sensors[SB9] E. J. Lind et al., “A sensate liner for personnel
monitoring applications,” in Proc. 1st Int. Symp.
Wearable Comput, 1997, pp. 98–105, doi: 10.1109/
ISWC.1997.629925.
Everyday-use, eyeglass-based displays: Lightweight eye display prototype by Minolta[SB10] I. Kasai, Y. Tanijiri, T. Endo, and H. Ueda, “Aforgettable near eye display,” in Proc. 4th Int. Symp.
Wearable Comput, 2000, pp. 115–118, doi: 10.1109/
ISWC.2000.888472.
Intelligent Agents: Foreshadowed agents like Alexa

2nd Int. Symp. Wearable Comput., 1998, pp. 50–57, doi:or Siri accessed via mobile devices.

10.1109/ISWC.1998.729529.
[SB5] J. Pascoe, “Adding generic contextual[SB11] B. J. Rhodes, “The wearable remembrance
agent: A system for augmented memory,” in Proc. 1st Int.

capabilities to wearable computers,” in Proc. 2nd Int.

Symp. Wearable Comput., 1997, pp. 123–128, doi: 10.1109/

Symp. Wearable Comput., 1998, pp. 92–99, doi: 10.1109/

ISWC.1997.629928.

ISWC.1998.729534.
Fitness and Healthcare: Wearable healthmonitoring and early smart watches.
[SB6] P. Lukowicz, U. Anliker, J. Ward, G. Troster,E. Hirt and C. Neufelt, “AMON: a wearable medical
computer for high risk patients,” in Proc. 6th Int.

schematics on a wiring board to show where wires should
be attached and connected.1 While Tom Caudell andDavid Mizell were pioneering this work with Boeing, Thad
Starner wrote a 1990 proposal to the US Air Force advocating “augmented realities” that used computer vision
to observe the user’s motion to control objects in virtual
reality. Steve Feiner’s use of “augmented reality” in thetitles of his inﬂuential papers in 1993 cemented the useof the term, and AR became one of the unifying themes
for the wearables community by the ﬁrst ISWC in 1997.
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involvement in today’s common standards.

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Gesture: Gesture recognition in a wristwatch form
factor.
[SB12] J. Rekimoto, “GestureWrist and GesturePad:
Unobtrusive wearable interaction devices,” in Proc. 5thInt. Symp. Wearable Comput, 2001, pp. 21–27, doi:
10.1109/ISWC.2001.962092.

Early AR work by the ISWC community foreshadowed recent products. For example, Niantic uses
location-based services and device-tracking AR onmon GO,
smartphones for their games, such as Poke
resulting in over a billion downloads. Similar frameworks
and functionality can be found in the ARQuake gamefrom ISWC 20003 and the Touring Machine from ISWC
1997, which used GPS to overlay information about
Columbia University’s campus using a head-tracked, seethrough, head-worn 3-D display. Industry, meanwhile, has

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WEARABLE COMPUTING

come full circle, with Boeing developing a task guidance
application for wiring harnesses using Google Glass.5

Task Guidance
Today, companies like Ox and TeamViewer use headworn displays to guide warehouse pickers to retrieve
inventory from the correct storage location to fulﬁlcustomer orders. Similarly, industry is using wearables to assist workers in data collection, inspection, maintenance, and repair tasks. Wearable
computers can even offer automated on-the-job
training for these tasks. Some of the ﬁrst ISWC
papers from CMU, Georgia Tech [SB2], and wearable
computer manufacturer Symbol (now Honeywell)
explored many of the interactions now commonly
available from these vendors.

Remote Collaboration
Another early industrially focused theme at ISWC
was using wearable computers to allow remoteexperts to help local workers complete tasks.
Remote personnel could converse with local workers, see their environment and even point at objects
in that environment [SB3]. Other work explored creating spatially oriented conference spaces.9 Today,
TeamViewer provides similar functionality on commodity wearables, and Augmedix uses Google Glassto allow remote scribes to help doctors take notes
and retrieve records in real time while interviewing
patients.

Context AwarenessModern smartphones routinely use context, such as
location, to help improve web searches (for example, ﬁnding a nearby restaurant for lunch). Such context-based services were the subject of early ISWC
papers. Google cites Ashbrook’s work12 when discussing how their services automatically detect
meaningful locations such as “home” and “work” tosuggest targets for navigation, and Google Maps AR
resembles an interface demonstrated by Thomas in
ISWC98.13 Modern context services leverage local
transmitters and computer vision [SB4] to better
locate the user, and activity recognition by on-bodysensors remains an active area of research in bothindustry and academia. Much of Pascoe’s [SB5] useof context to aid an ecologist’s observations ofgiraffes in a Kenyan game reserve is now commonplace in which most smartphones can tag images
with GPS location, date, and user notes, saved
directly in the image’s formatting.

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Fitness and Healthcare Sensors
Before Fitbit and ﬁtness smartphone applications,
ISW2000 exhibitor FitSense showed their FS-1,a whichused a shoe pod and heart strap connected wirelessly to a wristwatch to help users track pace, distance, calories burned, and heart rate. That same
year, Martin et al. described their ECG wearable,
which provided real-time feedback to the patient,either as a warning of impending medical emergency
or as a monitoring aid during exercise. At ISWC2002,
ETH-Zurich described their AMON wrist-based medical monitor [SB6]. Similar functionality can now befound in the Apple Watch.

Wireless Personal Area Networks
Today most technologically savvy users have heard ofBluetooth, but most are not familiar with the IEEE
802.15 standard that covers such personal area networks. Fewer still know that this standard started as
the “Ad Hoc Committee for Wearables Standards” in
1997. ISWC researchers were active in the earliest
days of the standard [SB8] and presented creative
alternatives such as using clothing or the human bodyas a carrier.11

A SURPRISING DEVELOPMENT:THE SMARTPHONE
Not all devices and ideas that were started in theInternational Symposium of Wearable Computers
have proven to be successful commercially (yet!). For
some trends, though, the research community waseven taken by surprise by the speed of commercial
adoption. One development that few in the community saw coming was the widespread adoption ofsmartphones, which have rapidly become a genericplatform for small wearable hardware. Features ofmany of the early applications of wearable computing
are readily apparent in currently available smartphone
applications such as when one compares the Touring
Machine created by Steve Feiner’s team to Google
navigation. However, few members of the researchcommunity, if any, anticipated that consumers would
be likely to spend so much time on applications thatheavily relied on touch interaction. While ARQuakefrom ISWC 20003 foreshadowed many of the elements
mon GO, the research community did notof Pokeanticipate that when an outdoor AR game did become
popular, it would be on a smartphone with the screen
held at arm’s length.

a

FitSense (exhibitor): http://wcc.gatech.edu/exhibition

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WEARABLE COMPUTING

COMING ATTRACTIONS
While the smartphone has sped the development andadoption of many of the ideas articulated in ISWC
over the years, there are many research directions
that are still formative, due to limitations in current
hardware or how wearables can interact with the user
currently.

provide some such functionality, their use is episodic
and limited as they often do not have access to onbody context continuously. Currently, such on-bodysensing requires signiﬁcant power, and interacting
seamlessly with the user through eyeglasses or earbuds requires advances in HCI such as using context
to know when, and in which modality, to interact withthe user so as to avoid interruption.

Electronic Textiles
ISWC researchers have long held a fascination withelectronic textiles (e-textiles), whether it be the technical contributions of weaving ﬁber optics or electrically conductive ﬁbers [SB9] into fabrics or thestylings of the ISWC Design Competition. Industry has
shown interest, as evidenced by several conferenceson smart textiles, Google’s Jacquard products, andVolt’s smart yarns. Yet, no iconic products have yet
emerged. If the main utility comes in the form of military or medical use cases, the general public may
never become acquainted with e-textiles, and, indeed,
several barriers to a consumer product seem apparent. Since users change clothes daily, any e-textile
integration must be inexpensive, and fashion may be abarrier as users often like to change the style ofclothes they wear. Outerwear, such as jackets thatchange less frequently and are less often washed, may
provide an opportunity, and, indeed, the Levi’s Jacquard Truck Jacket and Ralph Lauren Heated Jacket
are two such current products.

Gestures
High proﬁle news stories on gesture-based companies, such as Facebook’s acquisition of CTRL-Labs,
are regular ﬁxtures of tech blogs, and ISWC has
seen many papers on gesture over 25 years [SB12].
Yet, except in gaming, use of gesture is relatively
rare in consumer electronics. One reason is that it ishard for users to discover and remember speciﬁc
interface gestures. Sensor mounting locations for
detecting gestures are limited to what users will tolerate, which usually means using wristwatches,mobile phones, or eyeglasses. Such wearables
should provide feedback to the user while performing the gesture so that the user knows if they are
doing it correctly. Such visual or auditory feedback
while performing a gesture also limits the form factor of the device and the type of gesture that canbe performed. However, recent investigation into
movement correlation interfaces10 may point to an
intuitive solution where the eyes, hands, head, or
any body part might be used for interaction.

Everyday-use, Eyeglass-Based Displays
Optics design principles articulated by Spitzer in ISWC
1997 for eyeglass-based AR displays14 can be seen in
Epson’s Moverio and Google’s Glass line of products,
and in ISWC2000 Minolta [SB10] demonstrated how
holographic optical elements might be used to create adisplay that weighs 25 g. However, we have not yet
seen a display in an eyeglass form factor sell more than
1 million units. One reason is fashion: that most displays
are obvious when worn and most users want display
glasses that look like normal eyeglasses even when
they are being used. Other difﬁculties include discomfort due to overall weight (should be <75 g), weight on
the nose (should be <40% of overall weight), and battery life (preferably enough for all day use).

Intelligent Agents
Another concept introduced at ISWC [SB11] is the ideaof an intelligent agent that helps the user throughout
the day with remembering key thoughts and proactively providing information based on the user’s context. While Amazon’s Alexa and Google’s Assistant
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Haptics
Smartwatches and mobile phones often include avibrating motor for alerts; however, ISWC authors
have shown that haptic interactions can be much
more expressive.6 Challenges to more widespread
deployment of more expressive haptics are that
actuators are often bulky and require wired connections to relatively large batteries due to the amount of
power they consume.

AffectISWC was one of the ﬁrst conferences to receive
papers describing affective computing.8 Wearable
physiological sensors are now commonplace,embedded in watches and ﬁtness sensors, but useof inferred affect remains more restricted in its
use. One challenge is recognizing affect from low
level sensing. However, the popularization of emoticons and emojis for mobile messaging shows aclear desire to convey affect to conversational
partners.

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WEARABLE COMPUTING

Energy Scavenging
In some sense, power harvesting in the form of selfwinding watches is one of the oldest forms of wearable technology. Yet most consumer wearables
require more power than can be generated by casual
movement of the wrist. Even so, ISWC authors haveshown the viability of energy scavenging from footfalls7 and other human activities, and recent advancesin wireless backscatter technologies suggest that onbody sensors may soon commonly take advantage ofenergy scavenging.

2. W. Hamburgen et al., “Itsy: Stretching the bounds ofmobile computing,” Computer, vol. 34, no. 4, pp. 28–36,
2001, doi: 10.1109/2.917534
3. B. Thomas et al., “ARQuake: An outdoor/indoor
augmented reality ﬁrst person application,” in Proc.
Dig. Papers. 4th Int. Symp. Wearable Comput., 2000,
pp. 139–146, doi: 10.1109/ISWC.2000.888480.
4. T. Martin and D. P. Siewiorek, “Wearable computers,”
IEEE Potentials, vol. 13, no. 3, pp. 36–38, Aug./Sep. 1994,
doi: 10.1109/45.310937.
5. N. Statt, “Boeing is using Google Glass to build
airplanes,” The Verge, Accessed: Jul. 14, 2016. [Online].

CONCLUSION
The early wearable vision of a central processor in the
pocket, wireless body network, and sensors and interfaces distributed across the body has come to pass in theform of smartphones, smartwatches, smart earbuds,
and a myriad of other products vying for commercial viability connected over a low power (ﬁnally!), low latency,
high-throughput version of Bluetooth. Augmented reality
is a commonly used public term, and every year brings a
new attempt at commercial AR display hardware. Yet
there is much more potential for on-body devices thatcan be unlocked by the ISWC community. Wearable
computers are unlikely to compete with laptops or desktops in terms of computing power, network speed, or
storage space. However, wearables enable faster andmore convenient interactions, on-body physiologicalsensing, and perception from the point of view of theuser. While the pace of innovation on desktop interaction has slowed over the past 50 years, the relative
recency of viable on-body hardware and its potential fora more intimate relationship with the user ensures that
innovation will continue to accelerate in the wearables
ﬁeld for years to come.

Available: https://www.theverge.com/2016/7/14/
12189574/boeing-google-glass-ar-building-airplaneparts
6. S. Ertan, C. Lee, A. Willets, H. Tan, and A. Pentland,“A wearable haptic navigation guidance system,” inProc. Dig. Papers. 2nd Int. Symp. Wearable Comput.,
1998, pp. 164–165, doi: 10.1109/ISWC.1998.729547.
7. J. Kymissis, C. Kendall, J. Paradiso, and N. Gershenfeld,“Parasitic power harvesting in shoes,” in Proc. Dig.
Papers. 2nd Int. Symp. Wearable Comput., 1998,
pp. 132–139, doi: 10.1109/ISWC.1998.729539.
8. R. W. Picard and J. Healey, “Affective wearables,”in Proc. Dig. Papers. 1st Int. Symp. Wearable
Comput., 1997, pp. 90–97, doi: 10.1109/
ISWC.1997.629924.
9. M. Billinghurst, J. Bowskill, M. Jessop and J.
Morphett, “A wearable spatial conferencing space,”in Proc. Dig. Papers. 2nd Int. Symp. Wearable
Comput., 1998, pp. 76-83, doi: 10.1109/
ISWC.1998.729532.
10. C. Clarke, A. Bellino, A. Esteves, E. Velloso, and H.
Gellersen, “TraceMatch: a computer vision techniquefor user input by tracing of animated controls,” in Proc.
ACM Int. Joint Conf. Pervasive Ubiquitous Comput.,
2016, pp. 298–303, doi: https://doi.org/10.1145/

ACKNOWLEDGMENTS
Picking selected work to highlight from 25 ISWC editions totaling almost 800 papers was hard, very hard.
We thank Juyoung Lee for his very helpful searchable
database on ISWC publications.b

2971648.2971714
11. E. R. Post, M. Reynolds, M. Gray, J. Paradiso, and N.
Gershenfeld, “Intrabody buses for data and power,”in Proc. Dig. Papers 1st Int. Symp. Wearable
Comput., 1997, pp. 52–55, doi: 10.1109/
ISWC.1997.629919.
12. D. Ashbrook and T. Starner, “Learning signiﬁcant

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locations and predicting user movement with GPS,”in Proc. 6th Int. Symp. Wearable Comput., 2002,
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WEARABLE COMPUTING

14. M. B. Spitzer, N. M. Rensing, R. McClelland, and P.

DAN SIEWIOREK is the Buhl University professor of electrical

Aquilino, “Eyeglass-based systems for wearable
computing,” in Proc. Dig. Papers. 1st Int. Symp.

and computer engineering and computer science, Carnegie

Wearable Comput., 1997, pp. 48–51, doi: 10.1109/

Mellon University. Contact him at ds1p@andrew.cmu.edu.

ISWC.1997.629918.
TOM MARTIN is currently a professor in electrical and com-

KAI KUNZE is currently a professor at Keio Media Design,

puter engineering and the Deputy Executive Director of the

Keio University, Tokyo, Japan. Contact him at kai@kmd.keio.

Institute for Creativity, Arts, and Technology, Virginia Tech.

ac.jp.

Contact him at tlmartin@vt.edu.

78

THAD STARNER is a professor with Georgia Tech and a staff

KRISTOF VAN LAERHOVEN is a professor for ubiquitous

research scientist in Google’s Research and Machine Intelli-computing at the University of Siegen, Germany. Contact him

gence Group. Contact him at thad@gatech.edu.

at kvl@eti.uni-siegen.de.

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