I M A G E B Y G A R R Y K I L L I A N

reaping the advantages of standardization and the software-engineering experience that programmers already had from other Internet systems.

Adam Dunkels of SICS in Sweden developed the Contiki operating system that has significantly grown in popularity, particularly over the past decade. As the technology matured, device hardware could pack more compute power for the same energy budget, and the resource savings TinyOS delivered thus became less important. Exploiting this power, Contiki’s advantage over its predecessors lay in its flexibility and ease of coding applications. Indeed, today hackers, academic institutions, and companies are using Contiki because it remains lightweight, mature, and free; for example, Texas Instruments (a U.S. company) ships many of its Io T/ CPS devices (such as Sensortag) with the option of using Contiki.

At that time, the prevalent commu-
nications protocols operated over low-
data-rate, local-area networking (up to
approximately 50-meter distances) ra-
dio transmissions. 802.15.4-based pro-
sion agriculture, smart transport, and
autonomous vehicles—all representing
new classes of technologically enabled
systems. Recent studies have predicted
the impact of Io T/CPS on the European
Union’s GDP in 2025 by sector, with
“transportation” being forecast to cre-
ate the greatest value, with a total of
€245 billion alone, followed closely by
“healthcare,” “housing,” and “indus-
try.” 1 As in the rest of the world, Euro-
pean countries and the European Com-
mission have invested heavily in IoT/
CPS research, almost €200 million, re-
sulting in many cross-discipline, cross-
country technology advancements
unique in terms of their focus on the in-
tegration of such systems, particularly
at scale, their underpinning communi-
cations substrates, and, more recently,
their security and relationship to priva-
cy. In this article we describe highlights
of this work in more detail and present
what we believe are the main outstand-
ing challenges facing the field for Eu-
rope over the next decade.

The Integrated Approach

Two decades ago, a European named
Kevin Ashton coined the phrase the
“Internet of Things.” His vision of con-
necting sensor- and actuator-based
technology to the Internet unfolded an
active area of technological advance-
ment around the world that only in the
past few years has begun to find larger-
scale adoption and is finally becom-
ing a commercial reality. In parallel,
the University of California, Berkeley’s
TinyOS and Mote hardware combina-
tion dominated early academic ex-
perimental work on wireless sensor
networks, also making its way into var-
ious commercial products. While the
U.S. focused on designing new pro-
tocols and approaches to overcome
the intrinsic limitations of resource-
constraint Io T/CPS devices, the focus
in Europe was more on the integra-
tion of such systems to fulfil real ap-
plication needs. In particular, tools
to aid the building of devices and,
moreover, their applications became
the European emphasis, resulting in
mechanisms to ease programming
and systems engineering and, more
important, make such systems a natu-
ral extension of the Internet, the latter