Author Archives: rown

7. Copyright & Licenses

What is the copyright law, how is it evolved, and can we have a better one? What can we do meanwhile, before changing it, to reduce the harms of this existing law? These are the questions which I will try to cover in this post.
In previous posts we went over the software issues and discussed how using/developing free (libre) software is an ideal we need for our freedom (philosophy) and also it is made possible by some developers (practicality). We also argued how harmful it is to use/develop non-free computer programs. For software, I talked about copyleft idea and how copyright law only comes handy when trying to use copyleft licenses to promote free (libre) software. Because freedoms 0, 1, 2, 3 are necessary, copyright law cannot and must not restrict users on how they use their software (I am assuming it is Free Software).
Now we change gears, and try to answer the questions about other works such as scientific papers or art works, some uses of which are restricted by the copyright law. We will see how implementing the copyright law enforcement, in a crude way, has become unpractical and a danger to our privacy. Basically you have to watch everyone’s computer to see if they are copying your work illegally. And to achieve this goal you are creating much bigger issues than the copying ‘issue’, if you can call it an issue at all.

I am publishing this post on May 6th, the day against DRM (@DayAgainstDRM). DRM, to be more precise, stands for “Digital Restrictions Management” or simply “Digital Handcuffs”. Please check to find out more.
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6. Puzzle Series [#3: De Bruijn sequence]

I will discuss puzzle #3 here. Let me repeat the puzzle. You want to write a string $S$ of digits with minimum length, say $L= {\rm length}(S)$, to include all the $n$-digit numbers in base $b$. For example, if $n=3$ and $b=10$, then, we want $S$ to include 000, 001, …, 999 in it, as its substrings.

Proposition 6.1. A string $S$ with length $L=b^n+n-1$ digits, can include all the $n$-digit numbers in base $b$, as its substrings. This formula means that each digit you are appending, after first $n-1$ digits, will include a new substring, i.e. a distinct $n$-digit number. The proof will be a bit sketchy, but I think it is quite straightforward to make it rigorous.
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4. A List of Free Software

In this post, which I will add to it or edit as time goes on, you will see a list of the relevant free (libre) software that I use generally and for my work, presently as a grad student. These are the software without any power over its users and with no known malicious features. See this post for an intro to free software. I am also using this post as an evidence for practicality of free software.

Free (Libre) Software Laputa

Fig. 4.1) Free (Libre) Software Laputa. Image is taken from this talk.

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3. An Introduction to Free Software

I try to use free (freedom-respecting) software and avoid proprietary (aka non-free) software. I am not a software developer but a user as most of the public. This post deals with an introduction to free software and licenses. There is almost no technical details in this post, only philosophy. In this post, I will show you the arguments that why this philosophy is ideal and adopting it is necessary. In another post, I will show you that it is practical, for most of us if not all, to only use free software. I am doing it right now.
If you are a software developer, I hope you are already aware of the issues and use GNU GPL license or a compatible one for your programs and respect your client’s freedom, while promoting free software. If you use a proprietary operating system and got used to it, you can start gradually using free programs. After answering all your needs with free software, then you can, much more smoothly, go ahead and switch to an available free operating system, like GNU/Linux.

Free Software movement started by Richard Stallman¬†(RMS) around 1983. For the philosophy, I suggest you to go and explore the videos and audios in For a more detailed definition of free software see this page. Briefly, free software respects users’ four essential freedoms:
(0) to run the program,
(1) to study and change the program in source code form,
(2) to redistribute exact copies, and
(3) to distribute modified versions.
Now, the natural questions to ask. Why do we need all these freedoms? Why are you giving me this definition? What is wrong with using the plain old copyright law to deal with software? Let’s find out.
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2. Puzzle Series [#1, #2, #3]

Each ‘puzzle series’ post will be a few puzzles, which I have learned about watching videos, reading some random books, or I did come up with gathering ideas from here and there. By word ‘puzzle’, I informally mean a problem that can be stated easily and has at least one known solution which doesn’t involve fancy math. Usually I put couple of hours a week thinking about some of these puzzles and I really enjoy the process, and want to share this joy with you.
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1. Screencasting & Videos for Education/Research

In this post, I will write about how I am doing screencasting and why I am doing it. You can download this example or get it from youtube. Also, check out the thoughts I have related to using videos in education and research.


As I listed in the ‘Popularizing’ section in my webpage, there are quite a few people working professionally on popularizing science. Those are good examples of using video format instead of written format to communicate scientific ideas. During the history of human kind, the way knowledge transmitted was the oral way and not the written way. It has been a few thousand years that we have notations to write with, and communicate the knowledge. Finally, we have the equipment to talk again, instead of writing. And this time to all the people on earth. This post talks about one of the most simple and cheapest ways to make videos. It is called screencasting, which means recording your screen, possibly with your voice over it.
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0. This is preface

Hi everyone. This is my new blog. As most of other blogs, I will write about subjects I am passionate about. Currently includes physics, math, software and licenses, education, and my concerns on some laws. At the moment of writing this, professionally I am a grad student in physics trying to learn physics and how to do research, I also consider myself a math enthusiast and an okay teacher among some other things. is my webpage where this blog is a sub-domain of. This blog, hopefully, will be much more informal than a webpage. I think it will take couple of years before I find my voice.

A subject that I am passionate about and will write about soon is free software. I use free software defined I will write about it later. I also invite others to do the same. Remotely related, I have also problems with the copyright law and I think we must change it substantially. I will try to write about this in more detail, but in few words, I think, popularity shortage of the appropriate economical models to support authors and artists, is making some people believe that sharing these works is really an unjust thing to do and should be illegal as mostly they are. Some profit-blinded publishers and sellers are happy about this, and they actually try to push this. They try to make sharing (non-commercial redistribution of exact copies) less and less acceptable or legal, specially by calling it “piracy”.

Another similar subject, which I talk about often with friends, is the inefficiency of our educational system. This is a meaningful point in the context of our world wide web technology, I mean internet. There are people seriously thinking and working on this subject. See edX as an example. But I will try to reinvent some of the wheels, and maybe they might be able to roll smoother. Of course, I can only sketch the ideas, mostly by waving my hands on the air, as I only know a little physics and I cannot do this by myself. The educational works, like any software (computer program), are there to do a job, so similarly they should be free and I don’t mean gratis. Free to be used, shared, modified, and redistributed. These days I am trying to learn to make videos for my students. I am also learning just a little website design so that I can upload all the work with links on the main web page
Other than general education, I also have some concerns about theoretical physics education in graduate schools and I think there are ways to change it for better. I prefer the way PI works on physics education, compared to others.