Chrome very slow

My Gigabyte hanged again, probably because of overheating. Chrome became super slow after rebooting. It was eventually fixed after reinstalling. That is, sudo apt purge google-chrome-stable rm -rf ~/.config/google-chrome/ and then reinstall by downloading Chrome from another browser.   Update: the problem does not seem to be fixed somehow… But turned off hardware acceleration seems…

Levy process

IMHO, the Levy process is just a generalization of the Poisson process. For example, consider $latex X_t$ as the number of arrivals by time $latex t$ as in the Poisson process. We expect the followings will be satisfied $latex X_t =0$ for $latex t = 0$ Random variables $latex X_{t_2} – X_{t_1}$ and $latex X_{t_4}-X_{t_3}$…

Proof of Fourier inversion formula

I think I knew how to show it before. But suddenly just realize I can’t. Say let’s define $latex F(w) = \frac{1}{2 \pi} \int f(t) e^{-i wt} dt$ and the inverse transform $latex \hat{f}(t)= \int F(w) e^{i w t}dw = f(t)$. So we expect $latex f(t)=\frac{1}{2 \pi} \int \int f(\tau) e^{-i w\tau} d\tau e^{iwt}dw$ $latex…

Bandlimited channel

By Shannon-Nyquist theorem, a bandlimited signal can be completely reconstructed with $latex 2W$ samples per second. Think of the opposite way, this means that each second we have $latex 2W$ independent components that we can vary for each second. The total noise power per second is $latex 2 W (N_0/2) = N_0 W$ and as…

Confusing things

I guess I seem to be confused with the partition function from evidence. When they appear together, I don’t seem to be confused. But when they appeared in different contexts, I just got confused like falling into some illusion tricks. Given data and parameter , the evidence is simply . And , where the denominator…

Distributed representation

It sounds like a misnomer to me. I probably will just call it a “vector” representation. It doesn’t have the “distributed” meaning of scattering information into different places. For example, to recognize a cat with “distributed” representation, we may distribute features into like “does it has a tail?”, “does it have four legs?”, and “does…

LeCun’s first lecture

LeCun has a new course on deep learning this spring. I found two things he mentioned that worth jotting down. First, natural data lives in low-dimensional manifold. Probably I should have came across that before but it didn’t register earlier. Come to think of it. This is a very important fact. Second, as it is…

Framing and prospect theory

Asian disease problem illustrated that framing can alter one’s decision based on if we are emphasizing gain or loss. Prospect theory is just a fancy name to conjecture what happens when the utility function is indeed what economists believe.

Free energy

When we model probability of a variable $latex x$ by $latex p(x) = {e^{-\frac{F(x)}{T}}}$, $latex F(x)$ is often referred to as the free energy. The name is coming from historical reason. The Gibbs-Boltzmann distribution for a configuration is proportional to $latex e^{-\frac{H}{k_B T}}$. And the closest reason I found is from here $latex p(H,T) =…