
A few Wi-Fi transmitters and your house becomes a coprocessor - rbanffy
https://arstechnica.com/science/2018/04/researchers-show-how-to-turn-your-bedroom-into-a-computer/
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jessriedel
Tangent: What is the term for these sorts of introductions?:

> In computing, we have pretty much come to accept the idea that smaller is
> better. The smaller the features on a chip, the more transistors we can
> place, the more computation can be done.

This doesn't actually help the reader understand the contents of the article.
At best, it tries to make the reader care about the article by drawing a
vacuous comparison to a generic piece of conventional wisdom.

There's a similar thing going on when I try to Google for
recommendations/reviews for, say, an exercise app. Very often, the article
will begin with just absolutely useless words like

> Research shows that people who exercise are happier and healthier. But this
> fast-paced modern life doesn't always make it easy! There's just so many
> things to get done. How can we make sure we're exercising as efficiently as
> possible? Workout apps! But which ones? Let's take a look at some of the
> different workout apps available in the app store.

Is this sort of filler material being added because writers are getting paid
by the word (honest question), or is it actually demanded by the editors of
the websites because it attracts more readers? Or is it some sort of SEO
thing?

Just trying to understand this phenomenon.

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jpeloquin
Perhaps the thesis, antithesis, synthesis triad? Also known as the Hegelian
triad.

For the linked article, thesis = "In computing, we have pretty much come to
accept the idea that smaller is better." Antithesis = "Researchers are
proposing an idea to make your computer bigger." Synthesis = "They want to
turn your entire house into a co-processor."

I've seen this and similar story templates show up in articles and books on
writing, especially related to writing for a mass audience. They are supposed
to produce narrative tension and improve reader engagement. Results vary.

[https://en.wikipedia.org/wiki/Thesis,_antithesis,_synthesis](https://en.wikipedia.org/wiki/Thesis,_antithesis,_synthesis)

~~~
jessriedel
Thanks, that's useful.

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marshray
I'm not a physicist like the Ars writer, but I always kinda though that
computation requires energy consumption and non-linear elements to interact
with a signal. The only energy source in this experiment are the Wifi
transmitters and I don't see any nonlinear elements.

The paper abstract seems to define 'computation' as performing a Fourier
transform like an optical lens (I'm imagining a prism separating the
wavelengths). It also says "We can exploit the linearity of the computation
operation Y = GX in which the entries of Y are independent from each other."

So I don't see how this meets any useful definition of "coprocessor". Can you
use it to perform a NAND operation?

~~~
LolWolf
You have to be careful about what you mean by "linear"—linear programs are
P-complete, and all binary operations are linear over F_2 (including NAND,
etc), since all functions are polynomials over finite fields and the largest
polynomial over F_2 is of degree 2-1=1. There are many linear elements which
can generate arbitrary circuits and hence can (in principle!) implement any
finite circuit (e.g., processor).

I do agree, though, that in this case it's unclear how the 'coprocessor'
connection arises from the original statement given in the paper.

~~~
marshray
"Linear in F_EM" :-)

------
miscreanity
This seems similar to what Artemis Networks has been working on, although they
don't use the waves for computation but communication.

[https://www.artemis.com](https://www.artemis.com)

~~~
JPLeRouzic
Hi, I admit that when I read your comment, I wondered what it has to do with
the Ars article. In fact after thinking a bit I think you may have better
understood the Arxiv article than the guy at Ars.

Indeed the point of the Arxiv article is not about doing computations, it is
about Time Reversal/Wave front shaping.

The original contribution of the authors seems to be in infering the matrix to
do beam forming simply from CSI in any random environment.

Citation: " _We have demonstrated experimentally that any disordered medium
can be employed as reconfigurable analogue computation unit, subject to
appropriate wavefront shaping_ "

~~~
marshray
> beam forming simply from CSI in any random environment

Isn't this basically holography, just using a few discrete antennae rather
than an (approximately) continuous film medium?

~~~
JPLeRouzic
I have a good understanding of Wavefront shaping but holography is out of my
comfort area.

I DDG a bit and found that " _The difference between a hologram and a
conventional photograph is that conventional photography records intensity of
light while a hologram records both intensity and phase._ "

So maybe...

