349 karma · joined September 21, 2015
Lmao.
Yes, this is likely to be one of the most important events in human history. We are living through a special period of evolution on Earth.
Wow, really amazing if true.
P.S.: After looking into their paper, it's not that impressive. They use agent's internal states (LSTM cells, attention outputs, etc.) to predict whether it is early in the episode, or whether the agent is holding an object.
There are two ways to avoid this: 1. predict 8 high (coarse) bits, 8 low (fine) bits separately as in the original waveRNN paper. 2. use a mixture of logistic distributions as the predictive output as in the recent Lyra vocoder from Google.
Moreover, usually our brain cannot imagine something as sharp and real as GAN's output. It's more like a blurry image from VAE's output.
Doing this guarantees differential privacy, a strong privacy protection.
However, the major disadvantage of RAPPOR is that we get a collection of very noisy data points. Therefore, we need a very big collection to learn anything useful at all!
If the number of clients/users/records is small, RAPPOR is practically useless.
Prio, on the other hand, adds NO noise to client's reports. It uses crypto magic to compute some functions (mean/sum/...) on the collection of reports by a network of servers. Only outputs of these functions are known. No reports are leaked until at least one server is honest!
However, Prio has no guarantee that the computed output doesn't leak information about client's reports (in fact, it surely leaks some information). While, RAPPOR guarantees this protection statistically!
A current research direction is to add noise to the output of Prio as such it guarantees differential privacy.
If you trust Mozilla, then you have nothing to worry about, except the proof or program may be wrong ;)
Third-parties are for someone who doesn't trust Mozilla. Or that Mozilla could be compromised by an unknown adversary.
What would you do when the sensor returns negative wind speeds due to noise or errors?
The wind speed cannot be negative, or greater than speed of light. An expert in windmill can narrow down the prior distribution much more.
> But priors can be much harder.
Choosing a prior is hard because it requires thinking explicitly about the problem and its assumptions. It merely exposes our lack of expertise on the problem.
When you're lazy, you can pick a uniform prior Uniform(0, c) and call it a day.
> We can sharpen the problem. Say my number and yours are different. How do we tell who is right?
Forget about prior, say, we have 2 sensors which output two slightly different wind speeds. Which wind speeds is right? The lower one or the average speed.
This is a deep philosophical problem. However, it's a problem for any model.
> The prior will mostly wash out in any well-posed problem.
I don't think so. Any well-posed problem should include the prior, or else how can we tell: 2 data points is not enough?
> HN tends to invoke the Bayesian framework as a complete solution to inference [...]
Bayesian framework is indeed a complete solution to inference in a formal/logical sense. However, I agree that there are many problems in applying Bayesian framework to real world problems that requires serious thinking about our assumptions on the problem.
Both prior and likelihood are our model's assumptions. So, the prior validation problem is similar to the likelihood validation problem. To check a Bayesian model or any model, we need to bring the model out of the formal world, to the real world for validation.
Prior predictive simulation method, which generates random data points from the prior, is a good heuristic to check if the prior is NOT plausible.
[1]: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.11...
[1]: https://github.com/pymc-devs/pymc4
[2]: https://www.tensorflow.org/probability/
[3]: http://pyro.ai/
Prior distribution is a beautiful and logical mechanism for adding regularization, domain-specific knowledge to our model.
[1] Stan, a platform for statistical modeling http://mc-stan.org/
[2] Automatic Differentiation Variational Inference https://arxiv.org/abs/1603.00788
[3] Auto-Encoding Variational Bayes https://arxiv.org/abs/1312.6114
This is a bold statement with no physical evidence to backup and no idea how quantum computer works.
Next, the paper said: how about sampling the whole posterior distribution instead of finding only one point of maximum likelihood as classical GANs do. This is the point where the famous Markov chain Monte Carlo (MCMC) algorithms become useful. They use something called stochastic gradient Hamiltonian Monte Carlo, basically, it is a random walk algorithm, at each step, you follow a noisy gradient, as a result, you converge to the posterior distribution instead of a local minima as gradient descent does.
The paper claims that sampling the whole posterior helps to resolve problems with classical GANs. IMHO, this isn't a surprise claim, this is exactly what is good about Bayesian statistics.