Find a site called Resurchify that ranks journal papers. Another site we already used quite a bit is letpub.

# Category: Education

## coordinate transformation

I got confused over time of coordinate transformation for a point in space v.s. transformation of a point location with fixed coordinates. It turns out that the former is the exact reverse of the latter. I don’t include a proof here, but it should be self-evident. Also it is much easier to understand coordinate transformation…

## coursera-dl

Coursera-dl is a wonderful tool but authentication doesn’t work out of the box. It will work after adding cauth option in coursera-dl.conf as here.

## Multiple desktop with Ipad mini

As I continue to explore options for using Zoom for teaching, one thing I like a lot is that I can connect my laptop to a monitor and only show one of the screens on Zoom. This way I can easily control what my students can see and I can leave some “cheat sheet” or…

## 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…

## PDF-XChange and Docear

PDF-XChange is the best compatible pdf reader for Docear. In Linux, I couldn’t manage to open pdf PDF-XChange even I changed it to default pdf reader. But this thread solves this. Basically “…If you want you can test it for yourself. In Docear, please use “Tools and settings > Miscellaneous > Preferences” to open Docear’s…

## Install Docear to 18.04

Docear runs fine on Ubuntu 18.04 but not out of box. The culprit is the new Java. One has to restore back to jdk 8.0 to get it work.

## Docear Google Scholar fix

Docear’s google scholar fetcher was not working probably for several years. However, it can be easily fixed following this post.

## Docear export to latex

Docear is a very nice concept that unfortunately is quite broken because of lack of support. Export to Latex supposes to be a killer feature but as of 2018 it really does not run out of the box. A workaround is described here. Basically, a best solution is to use Saxon rather than using the export…

## Lagrange’s theorem, Euler’s theorem, Fermat’s little theorem, and a short introduction to groups

A group $latex G$ in the context of math is a simple algebraic structure with a product operation $latex *$. Naturally, the operator won’t be of much use if the structure is not closed under the operation. Namely, we would like to have $latex a * b$ also in $latex G$ if both elements $latex…