they are moving? Can you tell how
many people there are? It turns out
you can, because they are breathing…
So what other physiological signals
can you extract?
And these questions are extremely
intellectually interesting, but it’s not
just that; they have very practical and
useful applications to people’s lives!
You’re now working, through a start-up
called Emerald, to commercialize the
technology and develop some of those
applications—for instance, remotely
monitoring people’s health.
We talk a lot about the smart home,
but really the smartest thing a home
can do is to take care of us and our
health. Our vision is to have a technology that disappears into the environment; I don’t have to enter information
about my heartrate, or put some device
on myself and remember to charge it.
I don’t need to change my behavior in
any way, but still there is a home that’s
watching over my health and keeping
track of problems early on—or even before they occur—and alerting doctors
or the hospital or a caregiver.
That sounds promising. Where are you
in your efforts?
At this early stage, our focus is to
work with healthcare providers, on the
one hand, and with the biotech and
pharma industry, on the other. It turns
out there are many deep physiological
signals we can extract, so we need to
connect with people who understand
what those signals mean in the context
of diseases. I can tell you that my mom
is walking well or that she fell—that’s
the extent of it. I couldn’t tell you if the
patterns of information indicate we
should change the dose on her Parkinson’s medication.
One of the most consistently cited fea-
tures of your work is creativity.
In general, in almost all the stuff
I do, I’m driven by curiosity. I’m always interested in trying something
where I don’t know the answer, or
where I’m not sure whether the answer is “yes” or “no.”
Leah Hoffmann is a technology writer based in Piermont,
© 2018 ACM 0001-0782/18/10 $15.00
defined in the context of something
Multicast is a communications protocol in which you deliver the same
information to a group of destinations
But in networking, typically, that’s
not how it works. In networking, you
typically have unicast, where one sender transmits to a single destination.
Even when you are sending something
like broadcast television over the Internet, your broadcast is actually using
unicast. You have your server turning
that traffic to all the individuals who
are interested in it.
What Muriel and I did was try to
take that really beautiful, elegant
theory, and think about it in the context of real networks. I felt wireless
networks, in particular, might be the
right environment for this technology. Wireless is way more limited in
terms of data rate and bandwidth
than wired networks, and it’s also less
reliable. So network coding is an ideal
solution when you make an error in
In your recent work, you’ve used wire-
less signals to track people’s mo-
tions—even through walls. How did
you get that idea?
When we began, it was really curiosity. Let’s say there is a room and you
don’t have access to it. Can you tell if
there are people in the room? If you
can tell there are people, can you tell
how many people? When we tried that,
we didn’t really know whether or not it
was possible, and we certainly didn’t
know what kind of application you’d
use it for. All we knew is that we have
been able to track people using their
cellphones—so, using a wireless signal, but a wireless signal that is emitted
from a device. And we have some understanding of how wireless works in
an indoor environment and propagates
through walls and materials.
After your initial demonstrations were
successful, the questions got more
complex, and practical applications
began to present themselves.
Once we started working with it,
we began to have all these ideas—
why stop at just being able to see if
people are moving? Can you tell how
[CONTINUED FROM P. 120]
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