Monty Hall paradox

Probability topic is the fundamental concept of the statistics. And machine learning is closely related to statistics. That is why, understand the probability very important if you are doing research, statistics, and machine learning.

Monty Hall is a very interesting problem. It says, if you are given 3 doors to choose. One of them contains a car (which you want), the other two are goats (which you don’t want). After you made your choice, before opening the door, the host will open the door that you didn’t choose yet contains the goat (he knows which door has the goat). Now, if you are given an opportunity to change your choice to another door (which you didn’t choose earlier), are you going to change?

Because I am using the Openbox (window manager), and I believe that the laptop Fn+F8 (or whatever combination with Fn) doesn’t work properly on Linux. Because the combination is detected as Super+p (aka Win+p). As a result, I wrote a Perl script to solve the switching display/monitor/screen issue on my laptop.

[code language=“perl”] #!/usr/bin/perl

# This script requires xrandr, and several bash script created by arandr

use strict; use warnings;

These few days I was spending my whole time to understand this ROC (receiver operating characteristic) curve. In machine learning, ROC is a very common way to evaluate the prediction performance. The AUC (area under curve) of ROC indicates the accuracy of prediction of a classifier.

If you wish to learn more, these two links are the best resources: here and here.

I searched through tutorial and Q and A sites on how to do the plot of ROC and calculating the AUC. The answers were telling me about “cut-off”, “threshold”, or some weird terms. And some answers were telling me to use R package to plot the graph. WTF? I know all of these things. My question was, “How can I plot ROC curve with my classifier?!”

In my previous post, I mentioned about AAC and the ID3 tag. And I mentoined that

I have an AAC audio file (technically M4A) […]

I used Audacious previously, then change to DeadBeef. The main reason I changed was because I kept failing to play AAC audio file. What’s wrong? FFplay can play it, SMPlayer can play it, DeadBeef can play it, Clementine can play it, but Audacious cannot. Audacious has a AAC plugin, it should support AAC format.

When I was doing programming as a hobbyist, I thought that writing source code is to communicate to the computer. Then lately working as software developer, I realised that coding is not just communicating to the computer, it is also communicating with other software developers.

When we are working on a big project, working alone is impractical. Then we need to work as a team. Consequently, our coding style needs to be conformed to ease the code review. Because at the end, the code is belong to the team, not an individual. That is why, practicing “clean code” is very important.

I just found that, if I have an AAC audio file (technically M4A), and if I added the ID3 tag 2 (aka ID3v2), then the audio file will failed to be converted by ffmpeg.

It can be either converted to mp3

• using DeadBeef audio player, or
• remove the ID3v2 tag then convert

So, how to add the metadata like ID3 tag? Use the Kid3 and add the Tag 3 (aka APE tag). This will not affect how ffmpeg to read the file.

In the previous post (1 year ago), I mentioned the hibernation issue. I believed that it was related to the NVidia graphic card. Related forum can be found here.

But these few days, I notice that whenever I shut down the laptop, it will show the systemd messages. Previously, if I did suspend my laptop, then resume, then shut down will show only black blank screen, until the power off. I believe that the graphic card issue is being fixed with the recent update.

I used to like C language, because it is a basic of programming, and it is portable, and it is low-level. When writing program with C language, it is just like showing off your advanced programming skill, how you manage the memory, how you manage the pointers and creating the linked list. However, in terms of efficiency, C++ is much more powerful, because of object-oriented and the syntax.

Because I like C language, so I chose GTK+ over Qt for long time ago. Not only that, I am also fond of GTK+ desktop environments like GNOME, Xfce4, LXDE, Cinnamon, but not Mate. I feel that KDE is heavy weight.

Sometimes I read online articles, and these articles are usually long pages and have outlines at the beginning. These outlines are the hyperlinks to the subtopics headings. Technically, you click the outline hyperlink, your browser will browse to the “anchor”, the URL will append with hash (#). Therefore, it is useful for bookmarking, so that you can share the URL target on the topic to someone else, or re-visit your bookmark.

I am cognitive science student. That is why I learnt AI, computational linguistic, machine learning, expert system, etc. 

Since I was a researcher on Augmented Reality, then I applied my computing skills. After this, I became a non-computer related lecturer, and spent my time doing programming as a hobbyist. Then later I became computer science lecturer, yet still had to do programming as a hobbyist. Now as a software developer, I know what are the differences of these roles: lecturer, researcher, hobbyist, and a true software developer.