Category Archives: science

Autopilot

Lead by lidar

At the moment (April 2019), the economy is in a weird quantum superposition of doom (yield curve inversion) and exaltation, with Lyft recently joining the public markets (always loved the irony of the term…)

I’ve been talking to a few people involved in driverless cars and AI lately, asking them…. when? They usually tell me soon, the problem they have is that the main drawback with learned neural networks is that they are almost impossible to debug. You can try to get insight on how they work (see the fascinating Activation Atlas), but it’s really difficult to rewire them.

And it’s actually pretty easy to hack them — you can easily do some random addition to find noise that will activates the whole network. In the real world, you can put stickers at just the right location and… make every other car crash. Pretty scary…

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Kolmogorov Access

Back in undergrad, I remember being fascinated by the notion of Kolmogorov complexity in computer science.

Put simply, the Kolmogorov complexity is the minimal length (number of lines) of the code needed to generate a signal, would it be a mathematical sequence (such as one listed in the OEIS) or an image, irrespective to the size needed to store it. It bears deep relations with the notion of entropy (a great book on the topic is Information Theory, Inference, and Learning Algorithms by the late David MacKay.)

For example, a series of eight billion ones in a row would require 1GB of memory, but can be written in a few lines of code:

for i in 1:1e9; print 1; end

(To some extent, this is why computer science is often problematic, since one of the goal of a good code is sometimes to reduce its Kolmogorov complexity, but the final code does not show all the lines that have been erased to get there…)

In the field of arts, culture and science, this description seems naive: can you really generate a book based on a script, or has it infinite entropy?

Science is organized knowledge. Wisdom is organized life.
– Immanuel Kant

In the age of the Internet, can we do better?

update 6/10/2019: I’ve seen recently on Twitter the embodiment of these ideas, see Nicole R.‘s thread. Way to go!

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The wonders of West Berkeley

I do love Berkeley, with its wonderful atmosphere and its people, daring to live on a different beat!

The spring and the fall are the most notably beautiful, and walking in the street is always an amazement.

Berkeley in the spring

In the winter, you get the magnolia; in the spring come the fragrant wisteria and the gentle jasmine; the summer has the river flowing to the sea, and the fall, oh the fall with the ginkgo glowing gold on Russell street!

Berkeley in the fall

I’ve seen a few friends moving nearby, and they seem to enjoy every bit of it.

Here’s a few places to check out:

  • Skates to get a drink right at sunset
  • Casa Latina for the best tacos of the East Bay
  • Berkeley Bowl West is such a paradise for the grocery shopper
  • Cal Sailing Club lets you sail and windsurf for less than a dollar a day
  • Bette’s Diner has some amazing brunch
  • Market Hall Foods on 4th street has the best cheese selection I know, plus a hundred of other delicacies
  • Albatross is the oldest pub of Berkeley, with a great selection of beer, darts and pool
  • Ashkenaz has a great music programming; don’t miss Stu Allen’s Grateful Dead!
  • Sola Lucy is the only place to go for thrift shop

For the news, check out Berkeleyside.com and the East Bay Express (free, out every Wednesday.) There’s also a lot of other places closer to downtown which are unique: the Back Room, the Pacific Film Archive, Yoga to the people, Half Price Book, Café Panisse, the Strawberry canyon pool, the Skyline boulevard, the Butcher’s son restaurant, the Melo Melo kava bar, and so many other things!

Savant

In other news I was recently promoted to a staff position at Lawrence Berkeley National Lab!

It’s still tenure track (hopefully the position will be fully secured in two years from now) , but I’m getting closer to my childhood dream: to become a savant.

I am extremely lucky to be there, working on a major US scientific infrastructure project (ALS-U), in a fantastic lab with my window literally overlooking the Silicon Valley.

The golden gate

Right now, I’m mostly doing beamline design and simulation, with some wavefront sensing and adaptive optics. Lots of very challenging topics (we have to deal with a laser-like beam hundred times smaller than a hair blasting kilowatts of light), and I’m learning a lot along the way. Amazing times!

How I unlocked my Verizon Moto G6 and ditched my iPhone 6 because it was too slow

Recently, I bought a phone for my family visiting, because roaming costs are so incredibly high for no good reason, and because it becomes hard to navigate the world without the internet (booking, GPS, etc.) I bought at $99, and paid a $50 data plan from Verizon (good deal given that the phone the MSRP is $249, that it’s a very decent phone, and that you can use it anywhere with any carrier — it has GSM, CDMA and everything you need.)

On the back of the box, it was mentioned that the phone could be unlocked after $50 had been made. I had just bought $50 of credit for 1 month of 4G with Verizon.

When my parents left, I tried to unlock it. It was a bit confusing, but it did work!

You can find solace in successfully going through automated customer service

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Vision+Light

Somehow my art piece has been accepted! A delightful play on the wavelike behavior of light, and the particle0like behavior of silicon atoms, in a tribute to Malevich. Instant Classic!

Incoherent on coherent

You can now see it at the Vision+Light exhibition on Berkeley Campus, from February 20th to March 14th, 2019

Paul Valéry sur le mensonge

Bonne année 2019!

Ces deux dernières années aux Etats-Unis m’ont beaucoup fait reflechir, sur le plan personnel et politique, à la notion de verité, de transparence et d’honnêté, qui plus que jamais est nécessaire au discours civil.

Au centre de cette réflexion, ces quelques lignes de Paul Valéry, toujours juste.

Mensonge

Ce qui nous force à mentir, est fréquemment le sentiment que nous avons de l’impossibilité chez les autres qu’ils comprennent entièrement notre action. Ils n’arriveront jamais à en concevoir la nécessité (qui à nous-même s’impose sans s’éclaircir).

– Je te dirais ce que tu peux comprendre. Tu ne peux comprendre le vrai. Je ne puis même essayer de te l’expliquer. Je te dirais donc le faux.

– C’est là le mensonge de celui qui désespère de l’esprit d’autrui, et qui lui ment, parce que le faux est plus simple que le vrai. Même le mensonge le plus compliqué est plus simple que le Vrai. La parole ne peut prétendre à développer tout le complexe de l’individu.

– Paul Valéry, Tel Quel

On truth and its perils

What is true, what is false, what is wrong?

With the rise of large scale misinformation, this question has become more and more important, as it seems political parties around the world have reached the escape velocity of facts.

polarization in US politics really goes only one way…

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Hyperloonies

Mr Musk is having a hard time, and even though I have great appreciation for his making engineering look cool again, I won’t relent  as I believe his efforts are misguided.

Nothing can be so amusingly arrogant as a young man who has just discovered an old idea and thinks it is his own. – Sidney J. Harris

Today, I’ll talk about Hyperloop.

edit 12/18/2018: Hyperloop startup Arrivo is shutting down -The Verge — lol

edit 10/10/2019: Was the Ocean Cleanup Just a Pipe Dream? – Outside online
Jenny Allen: “Male privilege in science is a 24 year old guy with no formal training being called a ‘boy genius’, receiving millions of dollars in funding, and referring to qualified female oceanographers as ‘Ms’ instead of ‘Dr.’ when they critique his project.”

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XFELs as non-kinetic weapons

A family tale goes that my grandfather, who was working in an ammunition factory near Chatellerault which became under German control during WWII. As he was ordered by the German command to paint the factory, he chose to buy buckets of red and white, and paint the factory with a beautiful bull’s eye ornament, what didn’t escape the British RAF notice. They were able destroyed the critical facility that fell into the hands of the invader…

I’m not sure how much of this story is true. I do not have reason to doubt it, however!

As we celebrate the hundredth anniversary of the first world war, I can only think of the many ways, under the promise of surgical interventions, making war has become worse. But maybe — maybe — if we can keep the enemy from dropping bombs on us, we can be safer.
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