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ericjang

2,242 karma · joined February 8, 2015

evjang.com https://twitter.com/ericjang11
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ericjang··on Snap’s Rise and Fall: How a Big, Splashy IPO Prompted the Doubters to Keep Mum
If you don't mind me asking, what social media are your family members using? Are their friends on that platform too?
ericjang··on Progressive Growing of GANs for Improved Quality, Stability, Variation [video]
If it were memorizing training data, it would due poorly on a Wasserstein critic trained on a validation set drawn from the same data distribution.
ericjang··on Progressive Growing of GANs for Improved Quality, Stability, Variation [video]
This is a general problem for generative models, regardless of whether they are explicit latent density (variational autoencoders) or implicit density (GANs) or fully-observed (PixelCNN). To date no consensus has been reached in the research community on what the "right" way to evaluate a generative model is: e.g. Parzen Windows estimators, log-probability, ELBO, etc.

Yann Lecun himself (as of NIPS2016) was pretty critical of probability-based metrics, as those have strong dependence to the choice of model (e.g. if the model is poor the log-probability is meaningless).

In GANs, the critic and the generator are trained w.r.t. each other, reaching some kind of equilibrium. A recent proposal that seems to be "ok" for evaluating GANs was proposed by https://arxiv.org/abs/1705.05263, which is to train a separate critic on the generator, for use in evaluation (the generator never sees gradient information from this critic). This evaluation critic approximates the Wasserstein distance. One could imagine actually training the independent critic on a validation set of images not seen by the training set.

ericjang··on A newly discovered moon tunnel
This is a very wise answer! This reminds me of the movie "Iron Sky" which involves Nazis on the Moon. I found the film surprisingly intelligent (at least more than I expected) and had some visually nice political commentary.
ericjang··on New periodic orbits of the three-body problem
Maybe the laws of our math and physics are not invariant to space and time :)
ericjang··on Musk revises Mars ambitions
Is this an American cultural thing, or are other cultures just as averse to public swearing?
ericjang··on Here I Stand, at Age 80
He mentions at 14:00 the "Dark Brown" experience, where he went to Brown University to make the HyperText system. He says "he had to work under a torrent of insults from someone who he thought was his friend and HyperText got dumbed down."

Though he doesn't mention who the "friend" was, is it the much-beloved (by Brown CS dept) Andy van Dam (who is credited as the co-designer of HES)?

https://en.wikipedia.org/wiki/Andries_van_Dam

ericjang··on Articles on fractals, computer graphics, mathematics, demoscene and more
I met Inigo at an internship when I was just starting out my CS career and he was kind and patient enough to mentor me on all sorts of cool computer graphics. A quote from "The Prestige" comes to mind:

Oh, no, sir. This wasn't built by a magician. This was built by a wizard. A man who can actually do what magicians pretend to do.

He does things that I wouldn't have dreamed possible with fragment shaders and implicit geometry. https://www.youtube.com/watch?v=yMpG6qEb8js

IQ is a wizard and really inspired my interest in programming and math.

ericjang··on Andrew Ng is raising a $150M AI Fund
I would guess "environment simulators"? Environments are to RL as datasets are to supervised/unsupervised learning.
ericjang··on Confession of a so-called AI expert
she's
ericjang··on The Full 10-Page Anti-Diversity Screed Circulating Internally at Google
this is true. Source: I work at Google
ericjang··on Teaching Robots to Understand Semantic Concepts
Interesting points. What would you consider an adequate task that demonstrates a program/robot has acquired "semantic understanding"?
ericjang··on Interview with Ex Machina’s Scientific Advisor
Murray makes a number of nuanced comments about AI philosophy that I enjoyed. I've reproduced them below, but please see the full transcript in case I have taken quotes out of context:

- Is she conscious at all? Is she conscious just like we are? Is she conscious in some kind of weird alien way. You never really know.

- we’re pretty close to human brain scale computing already in the world’s fastest super computers. We’ll get there within the next couple of years. But that doesn’t mean to say we know how to build human level intelligence. That’s an altogether different thing. And also there’s controversy about how you make that calculation as well. I mean do you, what do you count? Do you count a neuron? How do you count the computational power of one neuron? Or one synapse? And some people, you know, it may be that some of the immense complexity in the synapse is functionally irrelevant.

- They’re just the process of turning the raw waveform into text. So that’s been cracked. But then again, real understanding of the words, that’s a whole other story. And with all today’s personal assistants, you know it can be cool and they’re gonna get better and better, they’re still way off displaying any genuine understanding of the words that are being used.

- But let’s suppose that it was a world where we were minded to put Asimov’s Laws into Ava. Well maybe Ava might reason that she is human. You know what is the difference between herself and a human? And maybe she would reason that she shouldn’t allow herself to come to harm. And therefore she was justified in what she was doing. Who knows?

- Of course there are people who want to build autonomous weapons and all kinds of things like that and you might say to yourself well I would very much like it if somebody was trying to pay attention to things a bit like Asimov’s Laws and say well you know, you shouldn’t build a robot that is capable of killing people. But that’s a law that the designers, or that would be a principle, if we were to have it, that the designers and engineers would be exercising, not one that the robot itself was exercising. So that’s the sense in which it’s not relevant toady because we don’t know how to today make an AI that is capable of even comprehending those laws.

- Nathan’s criticizing Caleb over going with his like gut reaction and his ego and not in like if he were to think through every logical possibility for every action he would never do anything. Which is kind of like directly against all these laws. Ava would never do anything if she could harm someone possibly down the road by you know burning fossil fuel, by being in a helicopter.

(My own commentary) This last point may be particularly relevant to researchers in Deep RL. Often we formulate off-policy RL problems as computing value functions that represent expected reward over optimal policies until the end of time. But maybe long-horizon reasoning is too computationally expensive (requiring agents to solve every trolley problem in its future and model the effect of burning fossil fuel on the environments), so some kind of rational ignorance is actually optimal in a compute-resource-restricted regime.

ericjang··on The secret to a long and healthy life? Eat less
Does that imply that lifting, building up one's body and consuming excess calories to bulk up is somehow stressful for the body's metabolic aging process?
ericjang··on Frighteningly Ambitious Startup Ideas (2012)
I'm grateful that there is such a wide spectrum of how to interpret the ambition of these companies between yours and the parent post's comment. Thanks :)
ericjang··on Are Pop Lyrics Getting More Repetitive?
For those interested in this topic, I highly recommend "The Song Machine", by John Seabrook. Music is no longer written by single songwriter-singer, it's manufactured on an assembly line to optimize for 'hits'. Hits are to record labels as unicorns are to VCs :)

https://www.nytimes.com/2015/10/18/books/review/the-song-mac...

ericjang··on Apple Watch can detect arrhythmia with 97% accuracy, study says
No quote in particular, but it seems unlikely that they would miss such a blatant dataset bias and fail to instrument their ML models with metrics besides accuracy. But then again, welcome to Silicon Valley :)

1 - 200/6158 = 97% is indeed a pretty suspicious coincidence though. I would assume/hope that they've shuffled a big dataset of recorded heart events (like the image in the TC article) and that the 200 people diagnosed with paroxysmal atrial fibrillation only rarely experience AF, so the number of true positives is probably far smaller than 1% of the dataset.

ericjang··on Apple Watch can detect arrhythmia with 97% accuracy, study says
I think the article is not precise with their wording, but the 97% is actually recall (i.e. detects 97% of the positives).
ericjang··on How standard portfolio theory changes when assets are technologies
My eyes glazed over at the vast number of priors introduced in this work. Why should I believe the assumptions hold?

In Machine Learning, the standard expectation of research papers is to empirically demonstrate the increased statistical power of the model over benchmarks, and I wish the authors demonstrated that their model aligns with historical reality.

I attended a talk recently by Aswath Damodaran where he explained that there are two types of investors, most often lying in disjoint sets: 1) number crunchers and 2) story tellers. Perhaps the success of tech companies (e.g. AMZN, GOOG, FB) can be explained in aggregate via the Wright model, but my feeling is that the majority of 'optimal portfolio distortion' these companies caused is mostly idiosyncratic to those specific companies, e.g. the "story tellers" have more information in the long-term behavior of a company. Consequently, aggregate modeling captures statistical correlation rather than causation, which can still make money but is not robust to long tails.

I think number crunching is only useful for short horizon portfolio selection.

ericjang··on Apple’s China Problem
Meta question: is there a "Hacker News of China" forum where I can find this article discussed from the Chinese perspective?
ericjang··on Mice treated with a protein from umbilical cord plasma showed improved memory
I'm reminded of this famous historical figure who inspired numerous vampire stories. https://en.wikipedia.org/wiki/Elizabeth_B%C3%A1thory
ericjang··on $1600 Ryzen PC has double performance in Photoshop than $5200 Mac Pro
Is it a fair comparison if the operating systems are different? A more adequate comparison would be if the Photoshop benchmark were run on a Mac Pro running the same Windows OS via Boot Camp.
ericjang··on When Pixels Collide
"They thought that search engines were a map of what people were thinking. But actually they were a map of how people were thinking. Impulse. Response. Fluid. Imperfect. Patterned. Chaotic."

- Nathan, Ex Machina (2015)

ericjang··on Unsupervised sentiment neuron
Why are people being so critical about this work? Sure, the blog post provides a simplified picture about what the system is actually capable of, but it's still helpful for a non-ML audience to get a better understanding of the high-level motivation behind the work. The OpenAI folks are trying to educate the broader public as well, not just ML/AI researchers.

Imagine if this discovery were made by some undergraduate student who had little experience in the traditions of how ML benchmark experiments are done, or was just starting out her ML career. Would we be just as critical?

As a researcher, I like seeing shorter communications like these, as it illuminates the thinking process of the researcher. Read ML papers for the ideas, not the results :)

I personally don't mind blog posts that have a bit of hyped-up publicity. It's thanks to groups like DeepMind and OpenAI that have captured public imagination on the subject and accelerated such interest in prospective students in studying ML + AI + robotics. If the hype is indeed unjustified, then it'll become irrelevant in the long-term. One caveat is that researchers should be very careful to not mislead reporters who are looking for the next "killer robots" story. But that doesn't really apply here.

ericjang··on Scaling your API with rate limiters
I disagree with the parent comment, but why is everyone downvoting this? It was a politely presented opinion, and the following discussion is entirely civil.
ericjang··on Artificial Intelligence: Past and Future
Repetition is a very persuasive technique. The more someone hears a claim, the more inclined they will believe it or at least attribute credibility to it, independent of the claim's merits.

Regardless of what one thinks regarding AI displacing jobs, there's been a remarkable growth spurt of technology and that begs lots of uncertainty about the future. When things get uncertain, people will speculate more, push their opinions on others, etc.

Sorry I'm not answering your question directly, but hopefully it suggests why we might be seeing all these "what's going to happen with AI" articles. You can bet there will be lots of opinions coming soon on "what should we do about it", but these are harder to tease out.

ericjang··on YC AI
Did you mean 'disrupt'? Hadn't heard of "disturb" before used in startup lingo.
ericjang··on YC AI
> The last part reminded me of google training a bunch of robot arms [1]. Haven't seen much being done with it, does anyone know if anything is being done with the data?

The data gathered using aforementioned robot arms is available here: https://sites.google.com/site/brainrobotdata/home

Google (specifically Google Brain Robotics) is continuing research on this. Exciting time to be alive.

ericjang··on Study: Immigrants Founded 51% of U.S. Billion-Dollar Startups
Issues of H1-B Visa abuse aside, I think this guy was trying to stop legal immigration: http://www.seattletimes.com/seattle-news/crime/kent-shooting...

I don't think articles like "Study: Immigrants Founded 51% of U.S. Billion-Dollar Startups" are all about anti-Trump, it's more like pointing out to the American public that immigrants are not a tax on the rest of society.

ericjang··on Japan to Unveil Pascal GPU-Based AI Supercomputer
NVIDIA is making a big bet on GPUs being the right abstraction layer for research/production, and is nearly pivoting the entire company around this. The software/developer tools layer is really important too. Custom AI chip makers (e.g. Nervana) hope to compete with NVIDIA despite having fewer resources. What are your thoughts on how a small AI chip company can best NVIDIA/other competitors?
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